Determination of the alteration in fatty acid profiles, sensory characteristics and carcass traits of swine fed elevated levels of monounsaturated fats in the diet

The present study was designed to determine the effects of supplemental fat or oil rich in oleic acid on the fatty acid profiles (FAP) and physical and sensory traits of pork carcasses. Sixty barrows and gilts were equally distributed among five dietary treatments consisting of a control diet of corn and soybean meal and four similar test diets that contained 10% animal fat (45.3 oleic), safflower oil (72.1 oleic), sunflower oil (80.9 oleic) or canola oil (57.7 oleic). The pigs were slaughtered after being fed these diets for 90 d at about 100 kg live weight. Carcass traits, FAP and sensory properties were evaluated for each treatment. First-rib fat thickness, ham muscling score and longissimus muscle areas were not different (P less than .05), but last-rib fat thickness was increased (P less than .05) with the supplemental dietary fat or oils. No differences existed for marbling scores, lean color, firmness or texture scores between the controls and pigs supplemented with either animal fat or safflower oil. However, pigs supplemented with sunflower or canola oil had lower marbling scores, lean color, firmness and texture scores. Fat became softer and more oily (P less than .05) with the supplemental dietary safflower, sunflower and canola oils. Sensory evaluation (loin chops) showed no differences (P less than .05) in sustained juiciness, tenderness or flavor intensity evaluations among treatments. However, the pigs fed canola oil had lower (P less than .05) flavor quality scores or overall palatability evaluations. Chops from the pigs fed canola oil also had 46% more off-flavors than all other treatments.(ABSTRACT TRUNCATED AT 250 WORDS)     

Performance and carcass characteristics of swine when fed diets containing canola oil and added copper to alter the unsaturated:saturated ratio of pork fat.

A 3 x 2 trial was conducted to determine the effects of adding canola oil (0, 5, or 10%) and copper sulfate (0 or 250 ppm Cu) to diets of growing-finishing swine on performance, carcass characteristics, and carcass fat fatty acid composition. The trial used 180 pigs (27 kg). Grower diets (.80% lysine for 0% canola oil diet) were given from 27 to 57 kg of BW and finisher diets (.64% lysine) from 57 to 102 kg. Diets were formulated to constant ME:lysine ratio within the grower and finisher phases. Over the entire growing-finishing period, the addition of canola oil to the diets resulted in linear improvements in rate of gain (P less than .05) and feed efficiency (P less than .01). Dietary additions of canola oil had no effect (P greater than .10) on resulting backfat thickness or longissimus muscle area but resulted in reductions (P less than .01) in loin marbling and color and carcass fat firmness, mostly noted in pigs fed the diets with 10% canola oil. Canola oil additions at 5 and 10% levels, respectively, resulted in a 23 and 37% reduction (P less than .01) in saturated fatty acids, 3 and 8% increase (P less than .01) in monounsaturated fatty acids, and 37 and 77% increase (P less than .01) in polyunsaturated fatty acids in the carcass fat compared with the diets without canola oil. The addition of canola oil to diets of growing-finishing swine had a favorable influence on animal performance and on increasing the unsaturated:saturated ratio of the carcass fat.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of dietary canola seed and soy lecithin in high-forage diets on cholesterol content and fatty acid composition of carcass tissues of growing ram lambs.

Phospholipids (soy lecithin) are important in the emulsification of lipids and may escape the rumen and influence the absorption of fatty acids in the small intestine. Our objectives were to determine the influence of dietary canola seed (high in unsaturated fatty acids) and soy lecithin in high-forage diets on total lipid content, cholesterol content, and fatty acid composition of carcass tissues. Forty-three Hampshire or Suffolk-sired ram lambs were weaned at 60 d of age (average 23.6 kg of BW) and assigned to a 2 x 2 factorial arrangement of treatments consisting of 1) basal diet (control = BAS), 2) BAS with 6% whole canola seed (CS), 3) BAS with 4.9% deoiled soy lecithin (SL), and 4) BAS with 6% CS and 4.8% SL (CSSL). The BAS diet consisted of 70% forage and 30% concentrate and contained 15% CP and 2.2 Mcal of ME/kg. Lambs were individually fed and given ad libitum access to feed to an average final BW of 52.1 kg. Longissimus muscle (LM) from the left side of each carcass posterior to the 13th rib (12 to 15 cm in length) was excised and the lean (LM) and corresponding subcutaneous (s.c.) adipose tissue were separated, frozen, and later used for lipid analysis by gas-liquid chromatography. In lean tissue, feeding lambs CS reduced (P less than .01) the proportion of total polyunsaturated fatty acids (PUFA) and feeding SL increased (P less than .01) the proportion of total PUFA. In s.c. adipose tissue, lambs fed CS had lower (P less than .01) saturated fatty acids (SFA) and lambs fed SL had increased (P less than .03) PUFA.(ABSTRACT TRUNCATED AT 250 WORDS)     

Fatty acid profiles and sensory and carcass traits of tissues from steers and swine fed an elevated monounsaturated fat diet

Twelve Angus X Hereford steers were assigned to either a control high-energy diet or a test diet consisting of 20% rapeseed at the expense of 20% corn. Twelve pigs were allotted to a control diet and two test diets containing either 10 or 20% canola oil (CO). Both CO and oil in the rapeseed contained 60 to 64% oleic acid. Cattle fed rapeseed exhibited little effect from the diet due to apparent indigestibility of the rapeseed. Total saturated fatty acids decreased from 40% in adipose tissue of the control pigs to 15% in the 20% CO-fed pigs. The ratio of monounsaturated to saturated fatty acids (M/S) increased from 1.19 in adipose tissue from control pigs to 3.63 with the addition of 20% CO to the diet. In muscle, the M/S ratio increased from 1.21 in control pigs to 2.46 in the 20% CO treatment group. The percentage of the saturated fatty acids in muscle decreased from 42% in the control to 23% in the 20% CO treatment. Significant increases in "oiliness" and decreases in fat firmness were observed when increasing levels of canola oil were fed. Sensory traits, cooking loss and shear-force values of pork chops were similar among treatment groups. In conclusion, monounsaturated fatty acid content can be elevated substantially in pork without adversely influencing the quality of the meat, thus producing a product perceived to be more healthful by the consumer.     

Influence of dietary palm oil supplementation on serum lipid metabolites, carcass characteristics, and lipid composition of carcass tissues of growing ram and ewe lambs.

The objective of this research was to determine the influence of dietary palm oil supplementation on carcass characteristics and lipid composition of tissues from growing lambs. Twenty-eight Suffolk x Hampshire lambs were weaned at 60 d of age (average 36 kg BW) and assigned to a 2 x 2 factorial arrangement consisting of diet (control [NPO] or 10.6% added dietary palm oil [PO]) and sex (ram vs ewe). The NPO diet (77% forage and 23% concentrate) contained 11.2% CP and 2.66 Mcal of ME/kg. Palm oil replaced molasses in the PO diet. Lambs were individually given ad libitum access to feed for 60 d to a final BW average of 50.1 kg. Lipid composition of the longissimus muscle and corresponding subcutaneous (s.c.) adipose tissue was determined by gas-liquid chromatography (GLC). Lambs fed PO were fatter (P less than .01) than lambs fed NPO (.77 vs .56 cm, s.c. fat). Diet had no effect on cholesterol content of lean tissue; however, feeding PO increased the saturated fatty acids of lean tissue. The s.c. fat from lambs fed PO had less (P less than .01) cholesterol (64.79 vs 89.67 mg/100 g) and more saturated fatty acids than that from lambs fed NPO. Ewes were fatter (P less than .01) than rams, yet they had less cholesterol content in the s.c. adipose tissue (68.71 vs 85.74 mg/100 g). High amounts of dietary palm oil fed to growing lambs caused changes in fatty acid deposition and cholesterol metabolism and may be a useful investigative tool to study lipid metabolism in growing ruminants.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of breed type and restricted versus ad libitum feeding on fatty acid composition and cholesterol content of muscle and adipose tissue from mature bovine females

Fatty acid composition and cholesterol content of muscle and adipose tissue from mature cows (N = 101) representing 15 breeds and crosses were determined. An initial group of cows was slaughtered after being fed slightly above the maintenance level for 2 wk; the remaining cows were fed either at the maintenance level or ad libitum for 84 d, then slaughtered. Samples of triceps brachii and longissimus muscle and subcutaneous and perinephric adipose tissue were obtained from each carcass. In addition, phospholipid and triacylglycerol fatty acids from total lipid extracts of triceps brachii muscle and subcutaneous adipose tissue were analyzed for 24 cows that were fed ad libitum or at the maintenance level for 84 d. Breed type effects on fatty acid composition were more pronounced in adipose tissue than in muscle tissue. Total lipid extracts of both triceps brachii and longissimus muscle from animals fed a maintenance diet for 84 d contained higher (P less than .01) percentages (3 to 8%) of polyunsaturated fatty acids (PUFA) and lower percentages (2 to 3%) of saturated fatty acids (SFA) than those from animals fed ad libitum for 84 d. This reflected significant variation in the fatty acids C14:0, C16:0, C18:2, C18:3 and C20:4 for both longissimus and triceps brachii muscle. Fatty acid composition within phospholipid and triacylglycerol fractions was similar regardless of maintenance or ad libitum feeding. Much of the variation in total lipid fatty acid composition appeared to be the result of differences in triacylglycerol:phospholipid ratios. Adipose tissue contained about twice as much cholesterol (mg/100 g wet weight) as muscle tissue. Both breed type and feeding group effects on cholesterol content of muscle tissue were nonsignificant. Values for cholesterol content of adipose tissue from cows fed restricted diets were higher than those from cows fed ad libitum (approximately 55 mg/100 g higher for subcutaneous and 25 mg/100 g for perinephric). The results show that changes in fatty acid composition of bovine tissues can be made genetically and by varying the energy level in the diet. Alteration of the cholesterol content of muscle tissue by these methods does not appear to be feasible.     

The effect of protein status of the pig on the recovery and amino acid composition of endogenous protein in digesta collected from the distal ileum

Barrows with an average initial weight of 55 kg were fitted with simple T-cannulas at the distal ileum. The animals were fed a protein-free diet that consisted of 79.7% cornstarch, 10% sucrose, 3% Alphafloc (a source of cellulose), 3% canola oil and a vitamin-mineral premix. The pigs were fed 700 g of diet twice each day, at 0800 and 2000. A balanced amino acid mixture or a saline solution was administered intravenously while the protein-free diet was fed. Ileal digesta were collected for 24 h following a 7-d adaptation period. The administration of amino acids reduced (P less than .05) the recovery of endogenous protein from 18.5 to 12.7 g per kg dry matter intake. For the amino acids, the reduction was only significant (P less than .05) for proline, from 3.6 to .6 g per kg dry matter intake. If the total endogenous protein losses are assumed to be constant and the differences in the amino acid composition of non-reabsorbed endogenous protein, as observed in this study, are used to calculate true ileal digestibilities, differences in the digestibilities of the indispensable amino acids are large (up to 7.4 percentage units for threonine). The amino acid composition of endogenous protein determined in pigs fed a protein-free diet and parenterally administered with amino acids should provide a better estimate for the calculation of true amino acid digestibilities when based on the determination of true protein digestibility by the 15N-isotope dilution technique.     

Influence of rapeseed meal, whole rapeseed, and soybean meal on fatty acid composition and cholesterol content of muscle and adipose tissue from ram lambs.

Twenty-four Suffolk x Hampshire ram lambs (average 46 kg) were assigned to one of three diets containing rapeseed meal (RM), soybean meal (SBM), or whole rapeseed-soybean meal (RSSBM) as the protein source. Diets contained 75% roughage, 14% CP and 2.0 Mcal of ME/kg and lambs were allowed ad libitum access to diets for 35 d. Lipid composition of the longissimus, semimembranosus, and triceps brachii muscles and their corresponding s.c. adipose tissue was determined by gas-liquid chromatography (GLC). The total lipid content in either muscle or subcutaneous fat was not different (P greater than .01) by diet. In lean tissue, palmitic and palmitoleic acids were higher and stearic acid was lower (P less than .01) in rams fed RM than in rams fed RSSBM or SBM, regardless of anatomical location. In the s.c. adipose tissue, the amounts of myristoleic, pentadecylic, and palmitoleic acids were lower and the amount of stearic acid was higher (P less than .01) in rams fed RSSM than in those fed RM or SBM, regardless of anatomical location. The semimembranosus and triceps brachii muscles from all treatments contained 12 to 19% more polyunsaturated fatty acids (PUFA) than the longissimus muscle. The cholesterol content of the three muscles was highest in SBM-fed lambs, lowest in RM-fed lambs, and intermediate in RSSBM-fed lambs. These results demonstrate that dietary treatments of the types used in the present study elicit changes in fatty acid composition of both adipose and muscle tissue without affecting the quantity of total lipid.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of calcium soaps of long-chain fatty acids on feedlot performance, carcass characteristics and ruminal metabolism of steers

Two trials were conducted to determine the effects of calcium soaps of long-chain fatty acids (calcium soap) on feedlot performance, diet digestibility, carcass characteristics and ruminal metabolism of steers fed diets (85% concentrate:15% corn silage) containing 0, 2, 4 or 6% calcium soap. In Trial 1, increasing calcium soap decreased (P less than .05) DM, CP and gross energy intake but increased total fatty acid intake. Feed to gain ratio tended to improve with increased calcium soap; gross energy conversion was not affected (P greater than .05) by diet. Average daily gain and hot carcass weight decreased (P less than .05) with addition of calcium soap; other carcass characteristics were not affected (P greater than .05). Apparent digestibilities of DM, N, energy and ash were not affected (P greater than .05) by calcium soap. Neutral detergent fiber digestibility increased linearly (P less than .08) with increasing calcium soap, whereas digestibility of total fatty acids was affected quadratically (P less than .05); fatty acid digestibility was similar among 0, 2 and 4% calcium soap diets but decreased for the 6% calcium soap diet. In Trial 2, increased calcium soap did not affect (P greater than .05) ruminal VFA concentrations, pH or in sacco NDF disappearance of orchardgrass following 12, 24 and 48 h of incubation. Calcium soap increased (P less than .07) ruminal concentrations of calcium soap fatty acids at 1, 2, 4 and 8 h postfeeding. Calcium soap did not improve performance of feedlot cattle fed high-concentrate diets. Further, calcium soap did not affect ruminal fermentation and did not dissociate significantly even when ruminal pH was below 6 for extended periods of time.     

The effect of feeding different protein-free diets on the recovery and amino acid composition of endogenous protein collected from the distal ileum and feces in pigs

Nine barrows with an average initial weight of 60 kg were fitted with simple T-cannulas at the distal ileum. The animals were fed four different protein-free diets according to an incomplete latin square design. Diet 1 (control diet) consisted of 79.7% cornstarch, 10% sucrose, 3% Alphafloc (a source of cellulose), 3% canola oil and a vitamin-mineral premix. Diets 2, 3 and 4 contained, respectively, 4% pectin, an additional 7% cellulose and an additional 10% canola oil, each included at the expense of cornstarch. Feces were collected during 3 d following a 7-d adaptation period. Thereafter, digesta were collected during two 24-h periods with a 24-interval between periods. The pigs were fed 800 g of feed twice at 0800 and 2000. Added pectin increased (P less than .05) the recovery of endogenous protein in ileal digesta from 19.8 diet (diet 1) to 24.0 g per kg dry matter intake. This increment was largely due to increases (P less than .05) in glycine and proline from 1.9 to 2.4 and from 6.2 to 8.4 g per kg dry matter intake, respectively. In feces, only added cellulose increased (P less than .05) excretion of endogenous protein (8.4 vs 11.1 g/kg DM intake) and of most amino acids. Including additional fat did not affect the quantity of endogenous protein and amino acids recovered in ileal digesta or feces. Small but significant differences (P less than .05) were observed in the amino acid composition of endogenous protein recovered in ileal digesta when the different protein-free diets were fed.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of feeding Aspergillus awamori and canola seed on the growth performance and muscle fatty acid profile in broiler chicken

The aim of this study was to examine effects of dietary supplementation with Aspergillus awamori and feeding canola seed on the growth and fatty acid profile in broilers. Twenty‐eight chicks (15 days old) were assigned to the following groups: (1) control, fed a basal diet; (2) awamori, fed the basal diet supplemented with 0.05% A. awamori; (3) canola, fed a diet containing 5% canola seed; and (4) canola + awamori, fed the canola diet supplemented with A. awamori (seven birds/group). Body weight gain was increased by A. awamori but not influenced by canola seed. Breast muscle weight was increased in either awamori or canola groups. Although plasma triglyceride and cholesterol were decreased by feeding A. awamori or canola seed, fat content in the breast muscle were increased, accompanied by decrease in saturated fatty acids and increase in unsaturated fatty acids. Moreover, decreased thiobarbituric acid reactive substance and increased α‐tocopherol content in the breast muscle was observed in all experimental groups. In conclusion, these results suggested that feeding canola seed and A. awamori might improve growth performance, and modified muscle fatty acid profile and α‐tocopherol content, suggesting that they may improve meat quality.     

Effect of dietary Rhodobacter capsulatus on cholesterol, triglycerides concentration, and meat quality of finishing pigs

The study was designed to investigate the effect of Rhodobacter capsulatus on serum and meat cholesterol, fatty acid composition in meat, as well as meat quality of finishing pigs. A total of 16 120-day-old Landrace female pigs of about 60 kg initial body weight were randomly assigned into two groups. The pigs were fed a supplemented diet with 0.04% dietary R. capsulatus or a control diet for 60 days. Total cholesterol and low density lipoprotein-cholesterol concentration in serum was significantly lowered ( P  < 0.05) in the pigs fed the R. capsulatus supplemented diet compared to the control diet. Carcass weight, carcass length, shoulder fat, back fat and loin fat thickness, longissimus muscle (LM) area, and color score did not differ significantly between the pigs fed the R. capsulatus supplemented diet and control diet. Among the nutrient composition of LM meat, neutral fat and triglyceride concentration were significantly ( P  < 0.05) reduced in the finishing pigs by dietary supplementation of R. capsulatus . The proportions of n-6 PUFA were higher ( P  < 0.05) in the pigs fed the R. capsulatus supplemented diet than in the pigs fed the control diet. The supplementation of dietary R. capsulatus to finishing pig diet played important roles in reducing serum cholesterol and meat triglycerides, as well as in increasing polyunsaturated fatty acid content in LM meat.     

Ovarian follicular characteristics, embryo recovery, and embryo viability in heifers fed high-fat diets and treated with follicle-stimulating hormone.

Postpubertal beef heifers (n = 55) were used to examine the effects of high-fat diets, independently of energy intake, on nonesterified fatty acid and lipoprotein metabolic patterns, ovarian follicular dynamics, and embryo recovery/viability after FSH superstimulation. High-lipid (HL) diets (5.4% added fat) increased (P < .01) serum concentrations of cholesterol, but not of nonesterified fatty acids, during the 35-d period before FSH treatment. Development of medium-sized (5 to 9.9 mm) follicles was enhanced (P < .05) during this period in heifers fed the HL diet. The HL diet increased total cholesterol (P < .05) and progesterone (P = .14) concentrations in follicular fluid obtained at ovariectomy (n = 10) 60 h after the onset of FSH treatment, but neither estradiol-17 beta nor androstenedione was affected. Granulosa cells recovered from FSH-induced, estrogen-active follicles in heifers fed the HL diet produced greater quantities of progesterone (P = .06) and less estradiol-17 beta (P < .05) in vitro than did granulosa cells from heifers fed the normal lipid diet. Dietary treatment did not influence FSH-stimulated recruitment of medium and large follicles, number of ovulations, embryo recovery, or embryo viability. Data suggest that increments in dietary fat intake can alter specific aspects of ovarian steroidogenic potential and can increase the population of medium-sized follicles theoretically available for maturation and harvest during the estrous cycle. However, conditions that limited the latter process in the current experiment are not understood and require further investigation.     

Dietary protein-induced changes in porcine muscle respiration, protein synthesis and adipose tissue metabolism

Growth rate, physically separable tissues of the ham and loin, heat production, skeletal muscle respiration and protein synthesis, and lipogenesis and lipolysis in s.c. adipose tissue were measured in a single experiment in which pigs were offered a 13 (n = 8), or 21% (n = 6) protein diet from 20 to 100 kg live weight. Pigs that were fed the 13% protein diet gained body weight slower, ate less, converted feed less efficiently and took 31 d longer to reach 100 kg live weight. Fat depth (cm) was greater (P less than .05) and loin eye area (cm2) was less (P less than .01) in pigs fed the 13% protein diet (2.6 vs 2.3 and 29.8 vs 35.3). Pigs that were fed the 13% protein diet had lower (P less than .05) ham and loin separable muscle and greater (P less than .05) ham and loin separable fat. The mean heat production was less (P less than .05) in pigs offered the 13% (22.49) vs 21% (24.63 MJ/d) protein diets. In the intercostal muscle preparation, total and Na+,K+-ATPase-dependent respiration (microliter O2.mg-1.h-1) were lower (P less than .05) in pigs offered the 13% (2.39 and .41) vs the 21% (3.89 and .68) protein diets. The energy used for the support of Na+ transport across membrane accounted for approximately 17% of muscle respiration. Absolute rates of protein synthesis in the muscle preparations were lower (P less than .01) at 13 than at 21% dietary protein. Lipogenesis in s.c. adipose tissue was not affected by dietary protein level. There was no difference in basal and norepinephrine-stimulated lipolysis between the two dietary protein levels.     

Effect of feeding high-oleic-acid peanuts to growing-finishing swine on resulting carcass fatty acid profile and on carcass and meat quality characteristics.

A high-oleic-acid peanut breeding line was used in a study designed to determine the effects of feeding swine diets containing elevated levels of monounsaturated fatty acids as a means to increase the level of monounsaturates and total unsaturates in the resulting carcass fat. Forty-eight pigs were allotted to four treatments that consisted of corn-soybean meal diets that contained 1) high-oleic peanuts (HOP), 2) regular commercial peanuts (RP), or 3) canola oil (CO), each added at a dietary level to provide 10% added fat/oil, and 4) a control diet with no added fat/oil. The oil of HOP averaged 75% oleic acid vs 60% for CO and 53% for RP. The pigs were fed the experimental diets from 33 to 102 kg BW, after which all pigs were slaughtered. All three dietary oil sources resulted in increases (P < .01) of monounsaturates in the backfat; the HOP diet resulted in the greatest increase (32% greater than control). Both CO and RP increased (P < .01) the level of polyunsaturates by nearly twofold; HOP resulted in a small decrease. Total unsaturates increased (P < .01) by 24, 24, and 27% for HOP, RP, and CO treatments, respectively, over that obtained from the control treatment. Carcass fat was softer/oilier (P < .05) from pigs fed CO and RP diets, but not from those fed HOP diets, compared with carcass fat of pigs fed the control diet. Dietary fat/oil source had no effect (P > .05) on other carcass compositional traits and various meat quality attributes.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of copper and fat addition to the diets of weanling swine on growth performance and serum fatty acids.

A 2 x 3 factorial experiment, encompassing three 28-d trials involving a total of 420 weanling pigs, was conducted to determine the effect of dietary Cu (5 or 250 ppm) and animal fat (0, 2.5, or 5%) on the performance and serum fatty acid profiles of weanling pigs. Pigs had ad libitum access to corn-soybean meal-based diets containing 10% whey and 5% fish meal and similar lysine:calorie ratios. Pigs were weighed and pen feed intakes were recorded weekly. Weekly blood samples were collected during the first two trials (n = 270) for serum fatty acid analysis. There was a Cu x fat interaction for ADG from d 1 to 14 (P less than .07) and over the 28-d experiment (P less than .05). The ADG of pigs fed 250 ppm of Cu increased, whereas the ADG of pigs fed 5 ppm of Cu was not affected as dietary fat increased. The addition of 250 ppm of CU increased (P less than .01) ADFI throughout the 28-d experiment. The addition of fat quadratically increased ADG (P less than .05) during d 14 to 28 and gain:feed ratios (P less than .01) during d 14 to 28 and over the 28-d experiment. The addition of fat decreased (P less than .05) the weight percentage of serum saturated fatty acids and increased (P less than .01) the weight percentage of serum monounsaturated fatty acids on d 28. The addition of 250 ppm of Cu decreased (P less than .01) the weight percentage of monounsaturated fatty acids on d 14 and 28.(ABSTRACT TRUNCATED AT 250 WORDS)     

Fat source and calcium level effects on finishing steer performance, digestion, and metabolism

A 111-d finishing study evaluated animal growth and carcass characteristics using 138 steers (366 kg) in a randomized complete block design with a 2 x 3 factorial arrangement of treatments. The dietary treatments consisted of no supplemental fat or 3.5% tallow or soybean oil soapstock (SS) fed with .6% and .9% dietary Ca. Fat increased DMI (P less than .05) but interacted with Ca level (P less than .05) for gain/feed and ADG. All diets containing fat or .9% Ca were converted more efficiently to gain than the .6% Ca, no supplemental fat diet (P less than .05). The .9% Ca interacted with fat source to decrease gain (P less than .05) and tended to decrease efficiency in the tallow diet but improved efficiency (P less than .05) and tended to improve gain in the no-fat diet. In the SS diet, .9% Ca had no effect on ADG, DMI, or efficiency of gain. Fat addition increased backfat (P less than .10) and interacted with Ca on hot carcass weight, final weight, and dressing percentage (P less than .05). Feeding fat increased the proportion of 18:0 (P less than .02) and decreased the proportion of 16:1 fatty acids (P less than .06) in intermuscular fat. A replicated 3 x 3 Latin square design, using six Holstein steers (349 kg) fed three diets, with no supplemental fat or 3.5% SS or tallow with 1.0% Ca, was used to explore the effects of fat sources when fed with high Ca on digestion and metabolism. Ruminal fluid pH was higher (P less than .10) when steers were fed fat. Adding fat did not affect (P greater than .10) duodenal or ileal pH, VFA proportions or total concentration, or ruminal liquid volume or flow rate. Liquid retention time was shorter and liquid rate of passage was higher (P less than .05) with dietary fat addition. Adding fat did not affect site or extent of starch or DM digestion. There was net synthesis of 16:0, 18:0, and 18:1 fatty acids in the rumen. When steers were fed tallow, synthesis of 16:0 and 18:0 fatty acids in the rumen was lower (P less than .10) than when steers were fed SS. Feeding fat tended to decrease (P = .11) bacterial N flowing at the duodenum but did not affect nonbacterial N or total N. Fat addition seems to affect ruminal kinetics, and the effects may vary with fat source, particularly relative to fatty acid synthesis and digestion.     

Characterization of lipid in loin and bacon from finishing pigs fed full-fat soybeans or tallow.

This experiment tested whether the lipid composition of pork could be altered by changes in dietary lipid, that what effects these changes would have on production and meat characteristics. Pigs were fed diets containing 10 or 20%+ extruded full-fat soybeans (FFS) or 4% tallow for a 3- or 6-wk finishing period, with a corn-soybean meal diet fed as a control. Seventy barrows and 70 gilts were allotted into seven treatment groups with four pens per group. Analysis was on 28 experimental units, which were composite samples from pens. The significance of treatment, sex, and treatment x sex interaction F-statistics was evaluated on chloroform-methanol extractable total lipid, triacylglycerol, phospholipids, cholesterol, individually fatty acids (FA), and the major classes of FA obtained from longissimus muscle and bacon. Treatment effects (P less than .05) were detected for cholesterol content of longissimus and for total lipid and phospholipid content of bacon. Treatment effects (P less than .01) were detected for monoenoic, dienoic, and polyenoic (P) FA in both tissues, and for saturated (S) FA in bacon (P less than .05). Treatment effects (P less than .001) were detected in both tissues for the P:S ratio. The P:S ratio increased 54% for longissimus and 100% for bacon in the pigs fed FFS for 6 wk compared with pigs consuming a corn-soybean meal diet.     

长期饲喂不同蛋白质水平饲粮对猪脂肪代谢相关基因表达的影响

本试验旨在研究长期饲喂不同蛋白质水平饲粮对猪脂肪代谢相关基因表达的影响。试验选用18头三元(杜×长×大)杂交28日龄断奶仔猪,随机分为3组,每组6个重复,每个重复1头。对照组[高粗蛋白质(HCP)组]采用符合NRC(2012)推荐营养需要的饲粮,试验组是根据NRC(2012)标准,在添加赖氨酸(Lys)、蛋氨酸(Met)、苏氨酸(Thr)、色氨酸(Try)4种必需氨基酸基础上,将饲粮蛋白质水平分别降低3%[中粗蛋白质(MCP)组]和6%[低粗蛋白质(LCP)组]。试验期125 d。结果表明:1)在肝脏中,与HCP组相比,LCP组显著降低脂肪酸合成相关基因乙酰辅酶A羧化酶(ACC)、脂肪酸合成酶(FAS)、苹果酸酶1(ME1)及锚蛋白1(ANK1)的基因表达量(P0.05);同时显著提高脂肪酸转运相关基因过氧化物酶体增殖物激活受体γ(PPARγ)及脂肪酸结合蛋白(FABP)的基因表达量(P0.05);而MCP组与HCP组相比,脂肪酸合成、转运相关基因表达量均无显著性差异(P0.05);与HCP组相比,MCP及LCP组均显著降低脂肪酸氧化分解相关基因、过氧化物酶体增殖物激活受体α(PPARα)、肉毒碱棕榈酰转移酶(CPT)的基因表达量(P0.05)。2)在背最长肌(LDM)中,MCP组中脂肪酸合成相关基因胆固醇调节元件结合蛋白(SREBP)、FAS、硬脂酰辅酶A去饱和酶(SCD)的基因表达量显著高于其他2组(P0.05);ACC及FABP在LCP组的基因表达量显著低于其他2组(P0.05);CPT基因表达量及LDM的肌内脂肪(IM F)含量在LCP及M CP组显著低于HCP组(P0.05)。3)肝脏和LDM中,各组甘油三酯脂酶(ATG L)及二烯酰辅酶A还原酶(DECR)基因表达量均无显著性差异(P0.05)。由此可见,在NRC(2012)基础上,适当的降低饲粮蛋白质水平(3%)可促进LDM中脂肪酸合成、转运相关基因的表达,但对肝脏中脂肪酸合成相关基因的表达无显著影响;适当的降低饲粮蛋白质水平(3%)可降低LDM及肝脏中脂肪酸氧化分解相关基因的表达,但并不增加LDM肌内脂肪含量。