当前位置:首页 >> 农林牧渔 >>

Abomasal Infusion of Butterfat Increases Milk Fat


J. Dairy Sci. 91:2370–2379 doi:10.3168/jds.2007-0894 ? American Dairy Science Association, 2008.

Abomasal Infusion of Butterfat Increases Milk Fat in Lactating Dairy Cows
A. K

. G. Kadegowda,* L. S. Piperova,* P. Delmonte,? and R. A. Erdman*1
*Animal and Avian Sciences Department, University of Maryland, College Park 20742 ?US Food and Drug Administration, Center for Food Safety and Applied Nutrition, College Park, MD 20742

ABSTRACT The objective of this study was to compare the effects of abomasal infusion of butterfat containing all fatty acids (FA) present in milk, including the short- and medium-chain FA, with infusion of only the long-chain FA (LCFA) present in milk, on the FA composition and milk fat yield in lactating dairy cows. Eight rumen?stulated Holstein cows, in early lactation (49 ± 20 days in milk) were used in a replicated 4 × 4 Latin square design. Treatments were abomasal infusion of the following: 1) no infusion (control), 2) 400 g/d of butterfat (butterfat), 3) 245 g/d of LCFA (blend of 59% cocoa butter, 36% olive oil, and 5% palm oil) providing 50% of the 16:0 and equivalent amounts of C18 FA as found in 400 g of butterfat, and 4) 100 g/d of conjugated linoleic acid (CLA, negative control), providing 10 g of trans10, cis-12 CLA. Fat supplements were infused in equal portions 3 times daily at 0800, 1400, and 1800 h during the last 2 wk of each 3-wk experimental period. Daily dry matter intake and milk production were unaffected by the infusion treatments. Butterfat infusion increased milk fat percentage by 14% to 4.26% and milk fat yield by 21% to 1,421 g/d compared with controls (3.74% and 1,178 g/d). Milk fat percentage and fat yield were decreased by 43% by CLA. Milk protein percentage was higher (3.70%) in CLA-infused cows than in control (3.30%), butterfat (3.28%), or LCFA (3.27%) treatments. Although LCFA had no effect on fat synthesis, abomasal infusion of butterfat increased milk fat percentage and yield, suggesting that the availability of short- and medium-chain FA may be a limiting factor for milk fat synthesis. Key words: lactating dairy cow, milk fat synthesis, de novo fatty acid INTRODUCTION The current milk component pricing system was introduced by the Federal Milk Marketing Administra-

Received November 26, 2007. Accepted February 15, 2008. 1 Corresponding author: erdman@umd.edu

tion in 2000. Accordingly, there has been a shift in the producer payment from the historic system based on the volume of milk (adjusted for fat content) to one based primarily on the amounts of milk fat and protein produced. The milk component pricing system provides a powerful economic incentive for dairy producers to produce high value milk components, namely fat and protein. Milk component yields are driven by both milk volume and component concentration. The diet of the dairy cow has no effect on milk lactose and mineral content (Sutton, 1989). Compared with milk fat responses, only modest effects of diet have been reported on milk protein concentration (Sutton, 1989). Milk fat is the milk component most easily manipulated by diet (Sutton, 1989). Reports in the literature have shown that milk fat percentage and yield can be reduced up to 46% (Piperova et al., 2000; Peterson et al., 2003) by milk fat-depressing diets containing high levels of grain and polyunsaturated fatty acids (PUFA). In contrast, very few studies have demonstrated consistent ways to increase milk fat concentration. Abomasal infusion of mostly saturated long-chain fatty acids (LCFA) tended to increase milk fat yield compared with infusion of mostly unsaturated fatty acids (FA) or mixtures of both (Drackley et al., 1992). Abomasal infusion of canola, soybean, or sun?ower oil did not signi?cantly affect milk fat percentage in lactating cows but changed milk FA pro?le re?ecting the FA composition of the infused oils (Christensen et al., 1994). Inclusion of fats and oils in the diet of lactating cows usually decreases the proportion of de novo FA produced by the mammary gland (Clapperton and Banks, 1985; LaCount et al., 1994). Short- and medium-chain FA (6:0 to 14:0, plus 50% of 16:0), constitute 50% of total milk FA and originate from de novo FA synthesis in the mammary gland (Palmquist and Jenkins, 1980). These FA are essential for the formation of milk triacylglycerols (Moore and Christie, 1979) and for maintaining the ?uidity of milk fat (Barbano and Sherbon, 1980). With exception of oleic acid, which is produced from stearic acid by the ?9desaturase system in the mammary gland, the LCFA in milk are derived from dietary sources (Palmquist and

2370

ABOMASAL INFUSION OF BUTTERFAT IN LACTATING COWS

2371

Jenkins, 1980). Experiments with milk fat-depressing diets in lactating cows have demonstrated that yields of short- and medium-chain FA synthesized de novo were reduced to a greater extent than LCFA yields (Loor and Herbein, 1998; Chouinard et al., 1999; Baumgard et al., 2002). These observations suggest that provision of short- and medium-chain FA via dietary means might enhance milk fat content, reducing the need for de novo synthesis. One could reason that a fat containing the FA composition identical to milk fat would provide the ideal fat supplement for milk fat production. Alternatively, if short- and medium-chain FA are not limiting, then a fat supplement containing only LCFA with a composition identical to that found in milk fat would be ideal for meeting the needs of FA that are typically absorbed from the diet. These conceptual approaches were used as means to potentially increase milk fat synthesis. The objective of this study was to compare the effects of abomasal infusion of butterfat containing all FA present in milk, including the short- and medium-chain FA, with infusion of only the long-chain FA present in milk, on the FA composition and milk fat yield in lactating dairy cows. MATERIALS AND METHODS Animals, Experimental Design, Treatment, and Sampling All procedures for this experiment were conducted under a protocol approved by the University of Maryland Institutional Animal Care and Use Committee. Eight rumen-?stulated multiparous Holstein cows in early lactation (49 ± 20 DIM) were used in a replicated 4 × 4 Latin square design balanced for carryover effects. Treatments were abomasal infusion of the following: 1) no infusion (control); 2) 400 g/d of butterfat as a source of short- and long-chain FA (butterfat); 3) 245 g/d of a LCFA mixture providing 50% of the 16:0 and equivalent amounts of C18 FA as found in 400 g of butterfat (LCFA); and 4) 100 g/d of commercial conjugated linoleic acid (CLA) mixture providing 10 g of trans-10, cis12 CLA/d, which served as a negative control. In the LCFA treatment, only 50% of the palmitic acid found in the butterfat was included, because 50% of palmitic acid is thought to be synthesized de novo (Palmquist and Jenkins, 1980). The LCFA mixture was a blend of 59% cocoa butter, 36% olive oil (Unilever, Englewood Cliffs, NJ), and 5% palm oil (GloryBee Foods Inc., Eugene, OR). In the butterfat treatment, butter oil was prepared from commercially available unsalted butter (Wellsley Farms, Natick, MA) melted at 37°C and separated from the protein coagulate by ?ltering. The CLA mixture was provided by Vitrus Nutrition

Figure 1. Fatty acid composition of postruminally infused butterfat and long-chain fatty acid (LCFA) mixture.

(Corcoran, CA). Amounts of postruminally infused individual FA in the LCFA mixture and butterfat are shown in Figure 1. The FA composition of the fat supplements is presented in Table 1. Experimental periods were 3 wk. The ?rst week of each period was without fat infusion to reduce carryover effects. This was followed by 2 wk of abomasal infusion. The fat was infused via tygon tubing (0.48-cm i.d, 0.64cm o.d; VWR Scienti?c, Bridgeport, NJ) that passed through the ruminal cannula, the rumen, the omasum, and into the abomasum, where the line was maintained using a 10-cm circular plastisol ?ange. The fat mixtures were liqui?ed at 50°C in air oven and mixed well before infusion. The amount of each FA mixture was divided into equal portions and manually infused 3 times a day (133.33 g of butterfat, 81.6 g of LCFA, and 33.33 g of CLA at 0800, 1400, and 1900 h). Actual amounts of infused fat were recorded each day. Patency and location of the infusion line inside the cow were checked on alternate days. Cows were housed in individual tie stalls and were fed a basal diet containing 55% forage and 45% concentrate (DM basis) to meet NRC (2001) nutrient speci?cations for a 650-kg cow producing 40 kg of milk containing 3.7% milk fat and 3.1% milk protein. Ingredient and chemical composition of the basal diet is given in Table 2. Diets were fed as TMR once daily at 0800 h. Forage and ingredient DM were measured weekly, and the TMR was adjusted accordingly to maintain a constant forage-to-concentrate ratio on a DM basis. Amounts of feed offered and refused were recorded once daily. Cows were milked twice a day at 0600 and 1600 h, and milk production was recorded electronically at each milking. Samples for milk composition and FA
Journal of Dairy Science Vol. 91 No. 6, 2008

2372

KADEGOWDA ET AL. Table 2. Ingredient and chemical composition of the basal diet Item Ingredient Corn silage Alfalfa haylage Corn grain, ground Citrus pulp Soybean meal Limestone Salt Magnesium oxide Sodium bicarbonate Potassium magnesium sulfate Dicalcium phosphate Trace minerals and vitamins1 Chemical composition DM, % CP RUP2 ADF NDF NEL,2 Mcal/kg Ca P Na Mg S K Cl DM, % 30.13 23.00 21.71 8.05 14.35 0.26 0.48 0.32 1.04 0.17 0.39 0.10 66.71 17.43 33.34 19.88 29.80 1.75 0.69 0.38 0.54 0.36 0.22 1.20 0.50

Table 1. Fatty acid composition of the butterfat, long-chain fatty acid (LCFA), and conjugated linoleic acid (CLA) supplements Fatty acid Butterfat LCFA CLA

g/100 g of FAME1 4:0 6:0 8:0 10:0 12:0 14:0 14:1 15:0 15:1 16:0 16:1 16:1 trans 17:0 17:1 18:0 18:1 cis-9 18:1 cis-11 18:1 cis-12 18:1 cis-13 18:1 cis-14 + 19:0 18:1 trans total 18:2n-6 18:3 22:0 Others Cis-8, trans-10 18:2 Trans-8, cis-10 18:2 Cis-9, trans-11 18:2 Cis-9, trans-13 18:2 Cis-13, trans-12 18:2 Cis-11, trans-13 18:2 Trans-10, cis-12 18:2 Trans-11, cis-13 18:2 Trans-11, trans-13 18:2 Trans/trans 18:2 Cis/cis 18:2
1

3.34 2.22 1.06 1.93 3.00 12.09 0.66 0.89 0.01 26.73 1.17 0.02 0.61 0.18 11.45 26.79 0.54 0.55 0.09 0.18 2.09 2.80 0.39 0.04 0.56 0.00 0.00 0.55 0.00 0.00 0.01 0.01 0.03 0.00 0.02

0.18

0.15

24.41 0.55

5.79 0.12

21.17 45.67

6.37 0.44 1.21

2.54 29.02 0.72 0.02 0.06 0.62 0.23 0.88 0.29 0.14 3.21 0.68 0.75 14.59 0.74 1.09 9.44 9.66 1.00 1.17 10.71 6.21

1 Trace mineral and vitamin mix combined (per kg of mix) 15 mg of Mn, 50 mg of Zn, 10 mg of Cu, 0.60 mg of I, 0.20 mg of Co, 0.30 mg of Se, 0.12 g of retinyl acetate, 0.40 g of cholecalciferol, and 0.05 mg of DL-tocopheryl acetate. 2 Calculated value.

Fatty acid methyl esters.

analysis were collected from the last 6 consecutive milkings of wk 3 of each experimental period. Milk fat, protein, and SCC were determined by infrared analysis (Foss Milk-O-Scan, Foss Food Technology Corp., Eden Prairie, MN) on fresh samples from individual milkings. A subset of samples from each milking was composited and frozen at ?20°C for subsequent analysis of individual FA. FA Composition Milk fat was extracted using a modi?ed Folch procedure (Christie, 1982) from composited wk 3 samples. The FA methyl esters (FAME) were prepared by mild transesteri?cation with 0.4 mol/L of H2SO4 in methanol (Christie, 1982) at room temperature, using trinonadecenoin (Nu-Chek Prep Inc., Elysian, MN) as internal standard (Piperova et al., 2002). The FAME were analyzed using an Agilent 6890 GC (Agilent Technologies,
Journal of Dairy Science Vol. 91 No. 6, 2008

Santa Clara, CA) equipped with a Supelco 2560 capillary column (100 m × 0.25 mm, 0.2 mm, Supelco, Bellefonte, PA) and a ?ame ionization detector. The column was maintained at 173°C isothermal. Hydrogen was used as carrier gas with a linear velocity of 26 cm/ s and split ratio of 1:100. The injection port and detector were maintained at 250°C. Detector air?ow was 400 mL/min, and hydrogen ?ow was 30 mL/min. Helium make-up gas was used at 30 mL/min. Individual FA and 18:1 isomers were identi?ed using GLC-463 standard mixture (Nu-Chek Prep Inc.). Although GLC conditions can be adjusted to quantify FAME from 8:0 to 12:0 with some accuracy, the very short FAME are volatile, water soluble, and require correction factors (Kramer et al., 1997). To avoid these dif?culties, short- and medium-chain FA were analyzed as FA butyl esters (FABE), which were mathematically converted to FAME and normalized to the FAME chromatogram. The original FABE procedure of Gander et al. (1962) was modi?ed as previously described (Piperova et al., 2000). Milk samples (200 L) in screwcapped glass tubes were heated at 100°C for 1 h in the presence of 1 mL of butyl alcohol and 200 L of acetyl chloride. Aliquots of the upper layer, containing FABE, were analyzed on a short 25 m × 0.2 mm fused silica

ABOMASAL INFUSION OF BUTTERFAT IN LACTATING COWS

2373

capillary column coated with HP1 (Hewlett-Packard, Avondale, PA) using a Hewlett-Packard 5880 GLC equipped with a split injector and ?ame ionization detector. Helium was used as the carrier gas at a ?ow rate of 2 mL/min with a split ratio of 45:1. After 5 min at 90°C, the column temperature was raised (4°C/min) to 106°C and at 10 min, programmed at 5°C/min to a ?nal temperature of 250°C. Standard mixtures, including GLC-60 (Nu-Chek Prep Inc.), were converted to FABE to aid in the identi?cation and quanti?cation of components. Individual CLA were analyzed as methyl esters using a Waters 2690 HPLC (Waters Associates, Milford, MA) separations module, equipped with a Waters 2996 PDA detector, and 3 Chromspher 5 lipid (250 × 4.6 mm, 5 M, Varian, Palo Alto, CA) HPLC columns in series. The mobile phase was 0.1% acetonitrile in hexane, at 1 mL/min, kept in a sealed bottle at ?15°C. The PDA detector was operated between 190 and 300 nm, and HPLC chromatograms read at 233 nm were used for quantitative analysis. Columns were maintained at 20°C. Typical injection volume was 1 L, containing 10 to 25 g of FAME. A CLA standard mixture (Nu-Chek Prep Inc.) was used to identify individual isomers. Details on the identi?cation and quanti?cation of the CLA isomers by HPLC analysis have been reported elsewhere (Sehat et al., 1998; Eulitz et al., 1999). Statistical Analysis Milk production, milk components, and FA composition data were analyzed as a replicated 4 × 4 Latin square using the MIXED procedure in SAS (SAS Institute, 2000). The ?xed effects were the treatments, whereas the random portion of the model included cow, square, and period. Probability of P ≤ 0.05 was considered statistically signi?cant. One cow was diagnosed with displaced abomasum and surgically repaired at the end of period 1. To allow for recovery from surgery, data from this cow were not included for experimental periods 1 and 2 (control and LCFA treatments, respectively). Because of missing data for this cow, the results are presented as least squares means. The largest standard error was reported in the treatments with unequal replication. Fisher’s protected least signi?cance differences were used for pairwise treatment mean comparisons. RESULTS The FA pro?le of the infused mixtures is presented in Table 1. Butterfat infusion provided short- and medium-chain FA (C < 16), in addition to palmitic acid and C > 18 LCFA. Also, the butterfat treatment con-

tained small amounts of CLA (0.63%) with cis-9, trans11 CLA being the predominant isomer. The LCFA mixture was formulated to provide equivalent amounts of LCFA of dietary origin, as in the infused butterfat, assuming that 50% of 16:0 in milk fat is derived from the diet. The CLA supplement contained 55% of CLA with cis-9, trans-11 (14.59%); cis-11, trans-13 (9.44%); and trans-10, cis-12 (9.66%) being the major isomers. Average daily DMI, milk production, and milk composition are presented in Table 3. The daily DMI and milk production was not affected by the infusions. However, butterfat infusion signi?cantly (P < 0.05) increased FCM (3.5%) compared with the control. Milk production ef?ciency (FCM/NEL intake) was lower with CLA infusions but did not differ due to butterfat or LCFA infusions from the control. Butterfat infusion increased milk fat percentage by 14% (P < 0.03) to 4.26% and milk fat yield by 21% (P < 0.02) to 1,421 g/d compared with controls (3.74% and 1,178 g/d). Infusion of LCFA had no effect on either milk fat percentage or milk fat yield, although milk fat yield was numerically (8.5%) higher compared with controls. Infusion of CLA decreased milk fat percentage and fat yield by 43% (P < 0.001), whereas milk protein percentage was 0.40 to 0.43 percentage units greater (3.70%; P < 0.01) compared with the other treatments. Concentrations (g/100 g of FAME) and yield (g/d) of individual FA in milk are shown in Tables 4 and 5, respectively. Fatty acid concentrations of individual short- and medium-chain FA that are synthesized de novo in the mammary gland did not differ between control and butterfat- or LCFA-infused cows. Compared with the controls, concentrations of C < 16:0 (total short and medium chain) FA, palmitic acid, or C > 16:0 FA were not altered due to butterfat infusion, whereas LCFA infusion decreased C < 16:0 and palmitic acid but increased C > 16:0 FA. Concentrations of the total monounsaturated FA (MUFA) were signi?cantly greater (P < 0.05) in cows infused with butterfat and LCFA compared with the controls (Table 4). The yield of short- and medium-chain FA was increased by 21% with butterfat (P < 0.05). Cows infused with butterfat produced milk with numerically the highest yield of 16:0 and signi?cantly greater yields of 14:0, 15:0, and 17:0 (Table 5, P < 0.02, 0.01, and 0.02, respectively). Milk of cows infused with butterfat was enriched with 14:1, 16:1, 17:1, and 18:1 cis, causing a 37% (P < 0.001) increase in the yield of total MUFA. Similar changes were observed in the yield of PUFA (18:2n-3, P < 0.004; 18:2i, P < 0.001; and 18:3n-3, P < 0.001) with the butterfat treatment. Yields of 18:1 cis-9 (26% increase; P < 0.005) and 18:2n-6 (43% increase; P < 0.002) FA were most affected by the LCFA infusion. Total saturated
Journal of Dairy Science Vol. 91 No. 6, 2008

2374

KADEGOWDA ET AL. Table 3. Least squares means for DMI, milk production, and milk composition from cows fed the control diet or the control diet plus abomasal infusion of conjugated linoleic acid (CLA), butterfat, or long-chain fatty acid (LCFA) supplements Treatment Item DMI, kg/d Milk kg/d FCM, 3.5% Ef?ciency, FCM/NEL Ef?ciency, FCM/DM Milk NE/NE intake Fat, % Fat yield, g/d Protein,% Protein, g/d Lactose, % SCC, 103/mL
a–c

Control 23.7 31.8ab 32.87b 0.78a 1.37b 0.53a 3.74b 1,178 b 3.30b 1,033 4.63a 102

CLA 24.1 29.9b 23.65c 0.55b 0.98c 0.41b 2.16c 661 c 3.70a 1,086 4.45b 174

Butterfat 24.2 33.7a 37.72a 0.83a 1.51a 0.56a 4.26a 1,421a 3.28b 1,061 4.59ab 205

LCFA 25.7 33.1ab 35.04ab 0.77a 1.38b 0.52a 3.79ab 1,279 ab 3.27b 1,085 4.70a 97

SEM 1.1 2.5 2.71 0.44 0.07 0.02 0.19 107.7 0.12 62.6 0.08 82.8

Least squares means within a row with different superscripts differ (P < 0.05).

FA were marginally increased with butterfat and LCFA infusion. Except for 4:0 concentrations, CLA infusion reduced concentrations (20%, P < 0.001) and yield (56%, P < 0.0001) of all short- and medium-chain FA and 16:0. Conjugated linoleic acid had similar effect on the yield of FA C > 16:0 (38% decrease; P < 0.001) and proportionally decreased all saturated FA (Table 5). Compared with the controls, the concentration (489%, P < 0.001; Table 6) and yield (336%, P < 0.001; Table 7) of total CLA increased in cows infused with CLA. This re?ected the increase in the percentage and yield of individual CLA isomers (Table 6 and 7). The cis-9, trans-11 CLA isomer was the predominant CLA isomer in the milk fat of cows receiving all treatments. Milk fat percentage of trans18:1 was increased in cows infused either with butterfat or CLA (Table 6), compared with the control or LCFA-infused cows. However, the yield of trans 18:1 was lowest in cows receiving CLA due to the reduction of milk fat (Table 7). Trans 11-18:1 was the predominant isomer in milk of cows receiving all treatments. The trans 18:1 and CLA isomer pro?le in cows infused with LCFA was similar to that in the control. DISCUSSION This is the ?rst study to examine the effects of postruminal infusion of de novo (short- and medium-chain FA) vs. dietary-derived (LCFA) FA on milk fat synthesis in lactating cows. Because our LCFA treatment contained nearly identical amounts of LCFA (C18 plus 50% of 16:0) as in butterfat, inferences about the role of short- and medium-chain FA on milk fat synthesis can be made by comparing the butterfat and LCFA treatments. In contrast, CLA infusion was used as a
Journal of Dairy Science Vol. 91 No. 6, 2008

negative control to demonstrate responsiveness of cows to changes in FA infusion. The CLA mixture provided 10 g/d of trans-10, cis-12 CLA and decreased milk fat yield by 43%. Consistent with other CLA infusion experiments (Chouinard et al., 1999; Baumgard. et al., 2000), de novo FA synthesis and FA desaturation were predominantly inhibited. Generally, DMI is affected by abomasal infusion of highly unsaturated FA (Bremmer et al., 1998; Benson et al., 2001) and to a lesser degree of saturated LCFA (Bremmer et al., 1998). The infusion mixtures in this study contained both saturated and unsaturated FA (Table 1), and the maximum amount of FA infused was limited to 400 g/d to avoid possible adverse effects on DMI (Drackley et al., 1992). Infusion of FA did not affect DMI and resulted in a marginal increase in milk production in cows infused with butterfat and LCFA treatments. Milk fat percentage and yield were signi?cantly increased with the butterfat but not with LCFA infusion treatments. The increase in total milk fat was more apparent when yields of individual FA were compared. The differences in the effects of butterfat and LCFA were associated with the short- and medium-chain FA provided by the butterfat. Earlier experiments (Storry et al., 1969) did not show changes in milk fat yield when synthetic tripropionin, tributyrin, tricaproin, tricaprylin, and tricaprin containing short-chain FA (3:0, 4:0, 6:0, 8:0, and 10:0) were intravenously infused for 2 d in lactating dairy cows. However, milk fat yield was increased by 16% during intravenous infusion of trilaurin (12:0) and trimyristin (14:0; Storry et al., 1969). Similarly, a 12% increase in milk fat yield was reported in lactating cows fed diets supplemented with coconut oil, containing predominantly 12:0 and 14:0 FA (Storry et al.,

ABOMASAL INFUSION OF BUTTERFAT IN LACTATING COWS Table 4. Least squares means for fatty acid composition of milk from cows fed the control diet or the control diet plus abomasal infusion of conjugated linoleic acid (CLA), butterfat, or long-chain fatty acid (LCFA) supplements Treatment Fatty acid Control CLA Butterfat
1

2375

LCFA

SEM

g/100 g of FAME 4:0 6:0 8:0 10:0 12:0 14:0 14:1 15:0 (iso) 15:0 (anteiso) 15:0 15:1 16:0 16:0 (iso) 16:1 16:1 trans 17:0 17:0 (iso) 17:1 (iso) 17:1 (anteiso) 17:1 18:0 18:1 cis-9 18:2i2 18:2n-6 18:3i3 18:3n-3 20:0 GLA4 Other Summations <16:0 >16:0 >20:0 MUFA5 SFA6 PUFA7
a–c 1

3.45 1.81a 1.24a 3.22a 4.01a 12.31a 1.14ab 0.23a 0.51 1.22 0.07 35.08a 0.36 1.63 0.04 0.79a 0.06 0.15b 0.43 0.21a 8.08ab 16.50b 0.47b 2.40b 0.14b 0.40b 0.10ab 0.03 0.55ab 29.21a 31.40b 0.16b 20.17b 72.47a 3.04c

3.04 0.83b 0.55b 1.55b 2.41b 10.96b 1.19ab 0.19b 0.47 1.25 0.03 35.41a 0.31 1.98 0.03 0.71b 0.06 0.18a 0.39 0.23a 8.91a 18.01b 0.58a 2.89a 0.09c 0.46a 0.11a 0.03 0.73a 22.47b 34.63ab 0.20a 22.04ab 66.76c 3.59a

3.52 1.54a 1.06a 2.83a 3.91a 12.65a 1.38a 0.22a 0.51 1.27 0.02 33.10ab 0.35 1.76 0.03 0.78a 0.06 0.19a 0.41 0.21a 7.31b 18.13b 0.60a 2.52b 0.11c 0.40b 0.09b 0.03 0.59ab 28.91a 32.60b 0.20a 22.13a 69.20ab 3.26bc

3.47 1.71a 1.17a 2.96a 3.73a 11.78ab 1.05b 0.23a 0.50 1.13 0.01 31.53b 0.33 1.22 0.03 0.74ab 0.06 0.20a 0.38 0.18b 8.47ab 20.84a 0.44b 2.93a 0.17a 0.43ab 0.12a 0.03 0.49b 27.74a 36.21a 0.20a 23.91a 67.93bc 3.57ab

0.36 0.10 0.08 0.19 0.25 0.37 0.08 0.02 0.03 0.04 0.02 1.33 0.03 0.16 0.01 0.03 0.00 0.01 0.03 0.01 0.42 0.84 0.03 0.14 0.01 0.03 0.01 0.00 0.07 0.89 1.35 0.01 1.19 1.38 0.16

Least squares means within a row with different superscripts differ (P < 0.05). Fatty acid methyl esters. 2 Nonconjugated 18:2 isomers. 3 Nonconjugated 18:3 isomers. 4 Gamma linoleic acid. 5 Monounsaturated fatty acids. 6 Saturated fatty acids. 7 Polyunsaturated fatty acids.

1971; Astrup et al., 1974). Pure saturated FA (12:0, 14:0, 16:0, or 18:0) fed to lactating cows (Steele and Moore, 1968b) produced variable changes in milk fat content but increased these FA in milk, suggesting that the proportions of FA from treatment supplements were increased in blood triacylglycerols. Comparable results were reported (Enjalbert et al., 2000) in lactating cows receiving duodenal infusion of palmitic, stearic, or oleic acids. In this study, infusion of butterfat signi?cantly increased the yield of FA with C ≤ 16:0, raising the over-

all milk fat yield compared with the other treatments. The increase was predominantly due to greater yield of 12:0 to 14:0 medium-chain FA. Short- and mediumchain FA are better absorbed than LCFA and are transported via the portal venous blood system (Grummer and Socha, 1989). Nevertheless, their transfer to milk fat may be reduced due to extensive metabolism by the extramammary tissues (Grummer and Socha, 1989). The apparent transfer ef?ciency of the abomasally infused FA was calculated (amount of FA excreted in
Journal of Dairy Science Vol. 91 No. 6, 2008

2376

KADEGOWDA ET AL. Table 5. Least squares means for yield of fatty acids in milk from cows fed the control diet or the control diet plus abomasal infusion of conjugated linoleic acid (CLA), butterfat, or long-chain fatty acid (LCFA) supplements Treatment Fatty acid Control 39.19a 21.02a 14.13a 36.52a 46.07a 144.31b 13.30b 2.76a 6.08a 14.24b 0.69 417.36a 3.47a 18.87b 0.31ab 9.24b 0.75a 1.44b 5.16ab 2.41b 90.10a 193.42b 5.68b 28.26b 1.12bc 4.73a 0.94bc 0.37a 6.46b 338.31b 361.86b 1.78bc 235.60b 849.97a 36.37b CLA 18.48b 5.98b 3.93b 10.96b 16.07b 73.24c 7.59c 1.31b 3.30b 8.27c 0.05 234.29b 2.14b 11.32c 0.14b 4.78c 0.41b 1.18b 2.76c 1.45c 60.54b 117.59c 3.84c 18.59c 0.62c 3.07b 0.77c 0.15b 4.73c 149.18c 226.44c 1.32c 142.08c 446.77b 23.97c Butterfat g of FAME /d 4:0 6:0 8:0 10:0 12:0 14:0 14:1 15:0 (iso) 15:0 (anteiso) 15:0 15:1 16:0 16:0 (iso) 16:1 16:1 trans 17:0 17:0 (iso) 17:1 (iso) 17:1 (anteiso) 17:1 18:0 18.1 cis-9 18:2i2 18:2n-6 18:3i3 18:3n-3 20:0 GLA4 Other Summations <16:0 >16:0 >20:0 MUFA5 SFA6 PUFA7
a–c 1 1

LCFA 45.43a 26.76a 15.53a 31.40a 48.99a 149.56ab 13.75b 2.81a 6.29a 14.45b 0.12 415.79a 4.24a 14.80bc 0.24ab 9.42b 0.72a 2.56a 4.53b 2.29b 105.14a 258.40a 5.68b 36.49a 1.23ab 5.31a 1.52a 0.38a 5.97bc 355.09ab 447.19a 2.49a 296.36a 881.84a 45.30a

SEM

49.30a 21.02a 14.56a 39.12a 54.58a 179.34a 19.70a 3.14a 6.96a 18.33a 0.15 476.21a 4.67a 25.10a 0.42a 11.21a 0.80a 2.58a 5.72a 3.08a 102.17a 256.41a 8.34a 35.62a 1.40a 5.55a 1.26ab 0.34a 8.29a 406.20a 458.74a 2.45ab 313.16a 986.96a 46.96a

5.75 2.50 1.59 3.78 4.75 14.51 1.65 0.26 0.61 1.60 0.29 46.61 0.55 2.11 0.10 0.90 0.08 0.28 0.54 0.42 8.85 15.77 0.58 2.23 0.17 0.45 0.15 0.06 0.68 30.42 33.11 0.13 20.13 78.03 3.27

Least squares means within a row with different superscripts differ (P < 0.05). Fatty acid methyl esters. 2 Nonconjugated 18:2 isomers. 3 Nonconjugated 18:3 isomers. 4 Gamma linoleic acid. 5 Monounsaturated fatty acids. 6 Saturated fatty acids. 7 Polyunsaturated fatty acids.

milk fat as a % of the amount infused) by subtracting the FA yield in the control treatment. It should be recognized that these apparent values re?ect changes not only in uptake but also in the net synthesis of FA. The overall transfer ef?ciency for C ≤ 16:0 in milk of cows infused with butterfat was 63% with transfer ef?ciencies of 44% (4:0), 0% (6:0), 0% (8:0), 33% (10:0), 67% (12:0), 83% (14:0), and 58% (16:0), respectively. Although 6:0 and 8:0 were most likely metabolized by other tissues, the transfer ef?ciencies of 10:0, 12:0, and 14:0 FA increased with the increase in chain length.
Journal of Dairy Science Vol. 91 No. 6, 2008

Storry et al. (1974) reported a net transfer of 42 and 48% for 12:0 and 14:0, respectively, to milk when protected coconut oil was fed to lactating cows. Compared with the control or LCFA-infused cows, yields of 10:0 and 12:0 tended to be higher, and yield of 14:0 was signi?cantly greater in milk of cows infused with butterfat. The potential of 12:0 and 14:0 to increase is greater than that of shorter chain length FA, probably because the ratio of lymphatic to hepatic portal vein uptake (greater lymphatic absorption) is positively correlated to FA chain length (Leveille et al., 1967). These

ABOMASAL INFUSION OF BUTTERFAT IN LACTATING COWS Table 6. Least squares means for conjugated linoleic acid (CLA), trans 18:1, and cis 18:1 isomers in milk fat of cows fed the control diet or the control diet plus abomasal infusion of CLA, butterfat, or long-chain fatty acid (LCFA) supplements Treatment Fatty acid Control CLA Butterfat
1

2377

LCFA

SEM

g/100 g of FAME CLA Cis-8, trans-10 Cis-9, trans-11 Trans-8, cis-10 Cis-10, trans-12 Trans-9, cis-11 Cis-11, trans-13 Trans-10, cis-12 Trans-11, cis-13 + 21:0 Cis/cis CLA Trans/trans CLA Total CLA Trans 18:1 4 5 6+7+8 9 10 11 12 13 + 14 16 Total trans 18:1 Cis 18:1 11 12 13 cis 14 + 19:0
a–d 1

Trace 0.40b Trace Trace Trace Trace Trace 0.04b Trace 0.09b 0.53b 0.01 0.01 0.17c 0.20b 0.27c 0.80 0.21b 0.47c 0.20b 2.34b 0.47b 0.27b 0.05c 0.13b

0.04a 0.83a 0.28a 0.02a 0.06a 0.44a 0.24a 0.05a 0.28a 0.35a 2.59a 0.01 0.01 0.22a 0.25a 0.40a 0.84 0.26a 0.56a 0.26a 2.81a 0.64a 0.29ab 0.08a 0.15a

Trace 0.51b Trace Trace Trace 0.01b Trace 0.03b Trace Trace 0.55b 0.01 0.01 0.20ab 0.24a 0.36ab 0.84 0.26a 0.52b 0.23b 2.67a 0.50ab 0.32a 0.07b 0.14ab

Trace 0.38b Trace Trace Trace 0.02b 0.01b 0.03b Trace Trace 0.44b 0.01 0.01 0.17bc 0.21b 0.28bc 0.81 0.22b 0.41d 0.20b 2.32b 0.52ab 0.27b 0.04d 0.13b

0.01 0.07 0.03 0.00 0.01 0.12 0.06 0.01 0.03 0.04 0.21 0.00 0.00 0.04 0.01 0.10 0.07 0.02 0.02 0.01 0.10 0.04 0.01 0.00 0.01

Least squares means within a row with different superscripts differ (P < 0.05). Fatty acid methyl esters.

FA might be expected to be metabolized to a lesser degree by the liver and be more available for the mammary gland (Grummer and Socha, 1989). About 60% of 16:0 present in the butterfat was transferred in milk, and yield of 16:0 tended to be higher compared with the control or LCFA-infused cows. Feeding studies (Steele and Moore, 1968c) have shown that dietary addition of pure palmitic acid caused the greatest increase in milk fat yield in dairy cows, compared with addition of myristic or stearic acid. Addition of palmitic acid increased percentages and yields of 16:0 and 16:1 FA in milk fat and decreased 10:0, 12:0, and 14:0 as well as 18:0 and 18:1. Similarly, yield of 16:0 was increased, and total FA in milk were signi?cantly higher during duodenal infusion of palmitic acid (Enjalbert et al., 2000). Palmitic acid is an important FA for the synthesis of triacylglycerol in the mammary gland (Hansen and Knudsen, 1987). Initiation of acylation of the sn-1 position is a prerequisite for triacylglycerol synthesis, and palmitic acid is the most preferred substrate for the initial acylation of L-α glycerolphosphate by acyltrans-

ferase to form sn-1-lysophosphatidic acid (Kinsella and Gross, 1973). It has been shown (Kinsella and Gross, 1973) that myristyl, stearyl, and oleyl coenzyme A were rapidly acylated when sn-1-lysophosphatidic acid was used as substrate but were poorly acylated without the latter indicating that these FA are taken up mostly in the second step of triacylglycerol synthesis. Infusion of LCFA did not signi?cantly alter milk fat yield. In contrast with other reports (Grummer, 1991; LaCount et al., 1994), yield of FA C < 16:0, including de novo FA, was not signi?cantly reduced by LCFA infusion, but rather it was maintained as in the controls. Butterfat and LCFA infusion mixtures contained equal amounts of LCFA (except for 16:0) resulting in a similar increase in milk FA C > 16:0. However, compared with the butterfat treatment, the proportion of C18 FA was considerably greater than the proportion of palmitic acid in the LCFA infusion mixture. Steele and Moore (1968a) reported that addition of cottonseed oil (containing 21% palmitic acid and 76% total C18 FA) or tallow (containing 30% palmitic acid and 60% total C18 FA) to the diet of lactating cows increased
Journal of Dairy Science Vol. 91 No. 6, 2008

2378

KADEGOWDA ET AL. Table 7. Least squares means for yields of conjugated linoleic acid (CLA), trans 18:1, and cis 18:1 isomers in milk of cows fed the control diet or the control diet plus abomasal infusion of CLA, butterfat, or longchain fatty acid (LCFA) supplements Treatment Fatty acid CLA Cis-8, trans-10 Cis-9, trans-11 Trans-8, cis-10 Cis-10, trans-12 Trans-9, cis-11 Cis-11, trans-13 Trans-10, cis-12 Trans-11, cis-13 + 21:0 Cis/cis CLA Trans/trans CLA Total CLA Trans 18:1 4 5 6+7+8 9 10 11 12 13 + 14 16 Total trans 18:1 Cis 18:1 11 12 13 Cis 14 + 19:0
a–c 1

Control

CLA

Butterfat g of FAME /d
1

LCFA

SEM

4.72b 0.05b 0.01b 0.04b 0.02b 0.35 0.02b 0.15b 5.63b 0.14 0.13 2.03bc 2.42b 3.22bc 9.50b 2.34b 5.58b 2.42b 27.78b 5.42bc 3.19b 0.64b 1.60b

0.25 5.24b 1.27a 0.06 0.32a 2.34a 1.50a 0.31 1.81a 1.65a 16.77a 0.08 0.09 1.50c 1.63c 2.63c 5.72c 1.73b 3.77c 1.72c 18.87c 4.07c 1.97c 0.48c 1.02c

7.28a 0.02b 0.04b 0.01b 0.30 0.01b 0.09b 7.87b 0.12 0.13 2.82a 3.44a 5.08a 11.76a 3.38a 7.31a 3.14a 37.18a 7.31a 4.47a 0.93a 2.03a

4.83b

0.63 0.24 0.09 0.29 0.13 0.05 0.17 0.22 1.51 0.03 0.03 0.23 0.25 0.40 1.17 0.36 0.67 0.24 2.82 0.68 0.39 0.06 0.16

0.04b 0.02b 0.35 0.00b 0.08b 5.40b 0.14 0.13 2.17b 2.61b 3.55b 10.31ab 2.39b 5.16b 2.53b 28.99b 6.57ab 3.54b 0.57b 1.61b

Least squares means within a row with different superscripts differ (P < 0.05). Fatty acid methyl esters.

stearic and oleic acids in milk fat but did not alter yield of 16:0. In contrast, yields of 16:0 and 18:1 were increased when a mixture of 64% palmitic acid and 34% total C18 FA was added to the diet of lactating cows (Steele and Moore, 1968b). In our study, yield of 16:0 in cows infused with LCFA was maintained at a level similar to that observed in the controls, whereas the yield of 16:0 was increased with butterfat treatment. The difference between these treatments may have been in?uenced by the C18 to 16:0 ratios in the infusion mixtures. It has been suggested (Steele and Moore, 1968a; Grummer,1991) that if de novo synthesis of 16:0 is inhibited by increased uptake of LCFA from the blood, the net yield of 16:0 in milk fat will depend on whether dietary transfer of 16:0 to milk fat is suf?cient to compensate for the decrease in de novo synthesis. In conclusion, the abomasal infusion of butterfat compared with LCFA demonstrated that milk fat synthesis could be regulated by the supply of short- and medium-chain FA in lactating cows. In addition, the increased availability of palmitic acid, the preferred substrate for the initial acylation of L-α-glycerophosJournal of Dairy Science Vol. 91 No. 6, 2008

phate, may have also stimulated triacylglycerol synthesis in the mammary gland. Compared with the controls, cows infused with butterfat produced milk fat with greater amounts of 12:0 and 14:0, MUFA, and PUFA. An increase in the proportions of unsaturated FA in milk fat is desirable because of the potential health bene?ts when included in human diet. However, further studies are needed to test and re?ne the role of short- and medium-chain FA on milk fat synthesis.

ACKNOWLEDGMENTS We gratefully acknowledge Benny Erez, Michael Dwyer, and Brian Speilman at the Central Maryland Research and Education Dairy Unit for their assistance with infusions, feeding, and animal care during this study. We also wish to acknowledge the kind donation of the CLA used in this study from Jesse Perez with Virtus Nutrition LLC located in Corcoran, California.

ABOMASAL INFUSION OF BUTTERFAT IN LACTATING COWS

2379

REFERENCES
Astrup, H. N., L. Vik-Mo, A. Ekern, and F. Bakke. 1974. Feeding protected and unprotected oils to dairy cows. J. Dairy Sci. 59:426–430. Barbano, D. M., and J. W. Sherbon. 1980. Polyunsaturated protected lipid: Effect on triglyceride molecular weight distribution. J. Dairy Sci. 63:731–740. Baumgard, L. H., B. A. Corl, D. A. Dwyer, A. Saebo, and D. E. Bauman. 2000. Identi?cation of the conjugated linoleic acid isomer that inhibits milk fat synthesis. Am. J. Physiol. 278:R179–R184. Baumgard, L. H., E. Matitashvili, B. A. Corl, D. A. Dwyer, and D. E. Bauman. 2002. Trans-10, cis-12 conjugated linoleic acid decreases lipogenic rates and expression of genes involved in milk lipid synthesis in dairy cows. J. Dairy Sci. 85:2155–2163. Benson, J. A., C. K. Reynolds, D. J. Humphries, S. M. Rutter, and D. E. Beever. 2001. Effects of infusion of long chain fatty acids on intake, feeding behavior and milk production of dairy cows. J. Dairy Sci. 84:1182–1191. Bremmer, D. R., L. D. Ruppert, J. H. Clark, and J. K. Drackley. 1998. Effects of chain length and unsaturation of fatty acid mixtures infused into the abomasum of lactating dairy cows. J. Dairy Sci. 81:176–188. Chouinard, P. Y., L. Corneau, A. Saebo, and D. E. Bauman. 1999. Milk yield and composition during abomasal infusion of conjugated linoleic acids in dairy cows. J. Dairy Sci. 82:2737–2745. Christensen, R. A., J. K. Drackley, D. W. LaCount, and J. H. Clark. 1994. Infusion of four long-chain fatty acid mixtures into the abomasum of lactating dairy cows. J. Dairy Sci. 77:1052–1069. Christie, W. W. 1982. Page 22 in Lipid Analysis. 2nd ed. Pergamon Press Ltd., Oxford, UK. Clapperton, J. L., and W. Banks. 1985. Factors affecting the yield of milk and its constituents, particularly fatty acids, when dairy cows consume diets containing added fat. J. Sci. Food Agric. 36:1205–1211. Drackley, J. K., T. H. Klusmeyer, A. M. Trusk, and J. H. Clark. 1992. Infusion of long-chain fatty acids varying in saturation and chain length into the abomasums of lactating cows. J. Dairy Sci. 75:1517–1526. Enjalbert, F., M. C. Nicot, C. Bayourthe, and R. Moncoulon. 2000. Effects of duodenal infusions of palmitic, stearic and oleic acids on milk composition and physical properties of butter. J. Dairy Sci. 83:1428–1433. Eulitz, K., M. P. Yurawecz, N. Sehat, J. Fritsche, J. A. G. Roach, M. M. Mossoba, J. K. G. Kramer, R. O. Adolf, and Y. Ku. 1999. Preparation, separation, and con?rmation of the eight geometrical cis/trans conjugated linoleic acid isomers 8, 10 through 11, 13-18:2. Lipids 34:873–877. Gander, G. W., R. G. Jensen, and J. Sampugna. 1962. Analysis of milk fatty acids by gas-liquid chromatography. J. Dairy Sci. 45:323–329. Grummer, R. R. 1991. Effect of feed on the composition of milk fat. J. Dairy Sci. 74:3244–3257. Grummer, R. R., and M. T. Socha. 1989. Milk fatty acid composition and plasma energy metabolite concentrations in lactating cows fed medium chain triglycerides. J. Dairy Sci. 72:1996–2001. Hansen, H. O., and J. Knudsen. 1987. Effect of exogenous long chain fatty acids on individual fatty acid synthesis by dispersed ruminant mammary gland cells. J. Dairy Sci. 70:1350–1354. Kinsella, J. E., and M. Gross. 1973. Palmitic acid and initiation of mammary glyceride synthesis via phospatidic acid. Biochim. Biophys. Acta 316:109–113.

Kramer, J. K. G., V. Fellner, M. E. R. Dugan, F. D. Sauer, M. M. Mossoba, and M. R. Yurawecz. 1997. Evaluating acid and base catalysts in the methylation of milk and rumen fatty acids with special emphasis on conjugated dienes and total trans fatty acids. Lipids 32:1219–1228. LaCount, D. W., J. K. Drackley, S. O. Laesch, and J. H. Clark. 1994. Secretion of oleic acid in milk fat in response to abomasal infusion of canola or high oleic sun?ower fatty acids. J. Dairy Sci. 77:1372–1385. Leveille, G. A., R. S. Pardini, and J. A. Tillotson. 1967. In?uence of medium chain triglycerides on lipid metabolism in rat. Lipids 2:287–294. Loor, J. J., and J. H. Herbein. 1998. Exogenous conjugated linoleic acid isomers reduce milk fat concentration and yield by inhibiting de novo fatty acid synthesis. J. Nutr. 128:2411–2419. Moore, J. H., and W. W. Christie. 1979. Lipid metabolism in the mammary gland of ruminant animals. J. Lipid Res. 17:375–378. Palmquist, D. L., and T. C. Jenkins. 1980. Fat in lactation rations: Review. J. Dairy Sci. 63:1–14. Peterson, D. G., E. A. Matitashvili, and D. E. Bauman. 2003. Diet induced milk fat depression in dairy cows results in increased trans-10, cis-12 CLA in milk fat and coordinate suppression of mRNA abundance for mammary enzymes involved in milk fat synthesis. J. Nutr. 133:3098–3102. Piperova, L. S., J. Sampugna, B. B. Teter, K. F. Kalscheur, M. P. Yurawecz, Y. Ku, K. M. Morehouse, and R. A. Erdman. 2002. Duodenal and milk trans octadecenoic acid and conjugated linoleic acid (CLA) isomers indicate that post-absorptive synthesis is the predominant source of cis-9-containing CLA in lactating dairy cows. J. Nutr. 132:1235–1241. Piperova, L. S., B. B. Teter, I. Bruckental, J. Sampugna, S. E. Mills, M. P. Yurawecz, J. Fritsche, K. Ku, and R. A. Erdman. 2000. Mammary lipogenic enzyme activity, trans fatty acids and conjugated linoleic acids are altered in lactating dairy cows fed a milk fat depressing diet. J. Nutr. 130:2568–2574. SAS Institute. 2000. SAS User’s Guide. Statistics, Version 8.0 Edition. SAS Inst. Inc., Cary, NC. Sehat, N., M. P. Yurawecz, J. A. G. Roach, M. M. Mossoba, J. K. G. Kramer, and Y. Ku. 1998. Silver ion high-performance liquid chromatographic separation and identi?cation of conjugated linoleic acid isomers. Lipids 33:217–221. Steele, W., and J. H. Moore. 1968a. The effects of dietary tallow and cottonseed oil on milk fat secretion in the cow. J. Dairy Res. 35:223–235. Steele, W., and J. H. Moore. 1968b. The effects of mono-unsaturated and saturated fatty acids in the diet on milk-fat secretion in the cow. J. Dairy Res. 35:353–360. Steele, W., and J. H. Moore. 1968c. The effects of a series of saturated fatty acids in the diet on milk-fat secretion in the cow. J. Dairy Res. 35:361–370. Storry, J. E., P. E. Brumby, A. J. Hall, and V. W. Johnson. 1974. Response of the lactating cow to different methods of incorporating casein and coconut oil in the diet. J. Dairy Sci. 57:61–67. Storry, J. E., A. J. Hall, and V. W. Johnson. 1971. The effects of increasing amounts of dietary coconut oil on milk-fat secretion in the cow. J. Dairy Res. 38:73–77. Storry, J. E., B. Tuckley, and A. J. Hall. 1969. The effects of intravenous infusions of triglycerides on the secretion of milk fat in the cow. Br. J. Nutr. 23:157–172. Sutton, J. A. 1989. Altering milk composition by feeding. J. Dairy Sci. 72:2801–2813.

Journal of Dairy Science Vol. 91 No. 6, 2008


相关文章:
三级试题2007年12月
Many customers like milk that has only a little butterfat in it. One ...the seller give the buyer the opportunity to deal with the price increases...
新目标八年级下册期末考英语试卷(1)
fat woman came into the shop on Saturday.She bought some eggs and some ...A.Butter,cheese and eggs. B.Milk. C.Meat and fish. D.Both A and B...
食品英语
Current dietary guidelines recommend that the fat intake in Western countries ...milk fat and is partly responsible for physical properties of butter such ...
牛津英语(2012年版)7A英语第二次月考(12月)
is fat Because he ________. B. likes to eat much D. is always ... ____3_____ and butter and a glass of milk ____4____ two __...
乳制品市场展望摘译
Butter production increases were not as robust, due to lower butterfat ...Butter and anhydrous milk fat prices showed strength on the prospects of ...
Unit2 阅读与写作
sugar,cereals such as rice, corn and wheat fat ? vegetable oil, butter and nuts fish, vegetables, milk and fruits minerals and ? vitamins 3. But ...
中南大学网络平台英语(中)1
The dairy department sells milk and milk products such as butter and cheese. Many customers like milk that has only a little butterfat in it. One ...
When ______ from milk, the remainder is called skim...
When ______ from milk, the remainder is called skim milk. A.all the butterfat is removedB.removing all the butterfat that...
更多相关标签: