Dietary fat and adipose tissue metabolism in ruminants, pigs, and rodents: a review

Effect of steam-flaked corn and soybeans on muscle and intramuscular fatty acid composition in Holstein calves

This study aimed to evaluate the effects of steam-flaked corn grains and soybeans on muscle fatty acid composition. Thirty Holstein bull calves (21 ± 3 d) were divided into 3 groups according to birth date and BW and were randomly assigned to receive fresh milk and a commercial pelleted starter diet containing extruded corn and soybean (ECS), steam-flaked corn and soybean (SFCS), or ground corn and raw soybean (GCS). The calves were fed the designated diet from 3 to 13 wk of age, after which they were slaughtered. The supraspinatus (CTM), longissimus lumborum (RLM), and spinalis dorsi (ERM) were analyzed to determine the chemical and intramuscular fatty acid composition. The fatty acid composition of muscle and its deposition differed among calves fed different starter feeds. Medium-chain fatty acid levels of the RLM and CTM were greater in GCS-fed calves than in ECS- and SFCS-fed calves ( < 0.05). Extruded processing increased the content of linoleic, linolenic, and arachidonic acids of the RLM ( < 0.05). The palmitoleic and -vaccenic acid content of the ERM were greater in GCS-fed calves than in ECS- or SFCS-fed calves ( < 0.05). No significant differences were observed among the 3 diets with respect to the stearic, oleic, linoleic, -9 -11 CLA, or arachidonic acid content of the ERM ( > 0.05). The levels of -3 and -6 fatty acids were similar among the 3 groups; a lower -6:-3 PUFA ratio was observed in GCS-fed calves ( < 0.05). The cereal processing method of the calf starter feed had no significant effect on the chemical composition of the CTM, RLM, or ERM. Therefore, different methods of processing corn and soybean in calf starter feeds had no effect on the chemical composition of the RLM, CTM, or ERM but had a significant effect on the intramuscular fatty acid composition.

Intestinal digestibility of long-chain fatty acids in lactating dairy cows: A meta-analysis and meta-regression

The objective of this analysis was to examine the intestinal digestibility of individual long-chain fatty acids (FA) in lactating dairy cows. Available data were collated from 15 publications containing 61 treatments, which reported total and individual FA duodenal flows and calculations of intestinal digestibility. All studies involved lactating dairy cows, and estimates of digestibility were based on measurements either between the duodenum and ileum (18 treatments) or between the duodenum and feces (43 treatments). Fatty acid digestibility was calculated for C16:0, C18:0, C18:1 (cis and trans isomers), C18:2, and C18:3. Digestibility of C18:0 was lower than for C18:1 and C18:3, with no difference in digestibility between saturated FA (C16:0 and C18:0). We weighted the studies by the reciprocal of the variance to generate best-fit equations to predict individual FA digestibility based on duodenal flow of FA and dietary independent variables. The flow of C18:0 negatively affected the digestibility of C18:0 and was also included in the best-fit equations for all other 18-carbon FA using duodenal flow characteristics. The type of fat supplemented had an effect on digestibility of individual FA, with whole seeds having reduced digestibility. Our meta-analysis results showed minimal differences in the digestibility of individual FA. However, C18:0 flow through the duodenum had a negative effect on the digestibility of several individual FA, with the largest negative effect on C18:0 digestibility. The mechanisms that reduce C18:0 absorption at high concentrations are unknown and warrant further investigation.

Feeding Iberian × Duroc cross pigs with crude glycerine: Effects of diet and gender on carcass and meat quality

Ninety (45 castrated males and 45 gilts) Iberian × Duroc pigs were used in this study. During the finishing period (95-160 kg body weight, 74 days) animals received conventional feed (control G0) or the same feed plus 5% (G5) or 10% (G10) of crude glycerine to partially replace wheat. In general, neither the diet nor gender affected ultrasound, carcass or meat quality parameters. The G10 had lower values of cooking loss and a* than the G5 and G0 groups. The fatty acids, C10:0, C12:0 and C18:3, in intramuscular fat were lower in both glycerine groups. Polyunsaturated fatty acids and 18:2 decreased and C20:0 increased at the subcutaneous fat of G10 animals. Castrated males produced carcasses with higher backfat thickness and fat content. Castrated males had a higher SFA content in subcutaneous fat than females (P<0.001). In conclusion, up to 10% crude glycerine could be used in the Iberian × Duroc diet.

Effect of protein or energy restriction during late gestation on hormonal and metabolic status in pregnant goats and postnatal male offspring

The objective of this study was to investigate the effects of maternal protein or energy restriction on hormonal and metabolic status of pregnant goats during late gestation and their postnatal male kids. Forty-five pregnant goats were fed a control (CON), 40% protein-restricted (PR) or 40% energy-restricted (ER) diet from 90 days of gestation until parturition. Plasma of mothers (90, 125 and 145 days of gestation) and kids (6 weeks of age) were sampled to determine metabolites and hormones. Glucose concentration for pregnant goats subjected to PR or ER was less (P < 0.001) than that of CON goats at 125 and 145 days of gestation. However, plasma nonesterified fatty acids concentration was greater (P < 0.01) at 125 and 145 days for PR and ER than CON. Protein restriction increased (P < 0.01) maternal cortisol concentration by 145 days of gestation, and ER decreased (P < 0.01) maternal insulin concentration at 125 days of gestation. Moreover, maternal amino acid (AA) concentrations were affected by nutritional restriction, with greater (P < 0.05) total AA (TAA) and nonessential AA (NEAA) for PR goats but less (P < 0.05) TAA and NEAA for ER goats at 125 days of gestation. After 6 weeks of nutritional recovery, plasma concentrations of most metabolic and hormonal parameters in restricted kids were similar to CON kids, except for reduced (P < 0.05) insulin concentration in ER, and reduced (P < 0.05) Asp concentration in PR and ER kids. These results provide information on potential metabolic mechanisms responsible for fetal programming.

Effects of different roughage sources and feeding levels on adipogenesis of ovine adipocytes

The objective of the present study was to conduct an adipogenic evaluation of different roughage sources and feeding levels during ruminant adipocyte differentiation in vitro. Six wether sheep were divided into a timothy hay feeding group (TFG, n = 3) and an Italian ryegrass straw feeding group (IFG, n = 3). The sheep were fed high-roughage (HR), medium roughage (MR) and low-roughage (LR) diets in a one-way layout design each over a 6-day period. Sheep serum samples collected on the last day of each dietary treatment were added to an adipogenic induction medium for differentiation of preadipocytes derived from sheep subcutaneous adipose tissue. The cytoplasmic lipid accumulations in the TFG serum-treated preadipocytes were significantly higher than those of the IFG-serum treated preadipocytes on day 12. Messenger RNA expression of CCAAT/enhancer-binding protein (C/EBP)-α, C/EBP-β, C/EBP-δ, fatty-acid-binding protein (aP2) and stearoyl-coenzyme A desaturase (SCD) were regulated by each serum treatment. This study shows that different roughage source diets and roughage-to-concentrate ratio diets can regulate adipocyte differentiation via ruminant blood composition.

Metabolism of early-lactation dairy cows as affected by dietary starch and monensin supplementation

The objective of this study was to evaluate the effect of dietary starch content and monensin (MON) on metabolism of dairy cows during early lactation. Before parturition, primiparous (n=21) and multiparous (n=49) Holstein cows were fed a common controlled-energy close-up diet with a daily topdress of either 0 or 400mg/d monensin. From d 1 to 21 postpartum, cows were fed a high-starch (HS; 26.2% starch, 34.3% neutral detergent fiber, 22.7% acid detergent fiber, 15.5% crude protein) or low-starch (LS; 21.5% starch, 36.9% neutral detergent fiber, 25.2% acid detergent fiber, 15.4% crude protein) total mixed ration with a daily topdress of either 0mg/d monensin (CON) or 450mg/d monensin (MON), continuing with prepartum topdress assignment. From d 22 through 63 postpartum, all cows were fed HS and continued with the assigned topdress treatment until d 63. Cows fed HS had higher plasma glucose and insulin and lower nonesterified fatty acids (NEFA) than cows fed LS during d 1 to 21 postpartum. Cows fed LS had elevated early-lactation β-hydroxybutyrate (BHBA) compared with cows fed HS. Cows fed HS had greater insulin resistance and increased plasma haptoglobin in the early lactation period. There was no effect of MON on postpartum plasma NEFA. Cows fed MON had higher plasma glucose compared with CON cows, which was driven by a MON × parity interaction in which primiparous cows fed MON had greater plasma glucose concentrations than cows fed CON. Cows fed MON had lower plasma BHBA compared with CON, which was contributed to by a MON × parity interaction in which primiparous cows fed MON had lower BHBA concentrations than CON. Starch treatment had no effect on overall liver triglyceride content. Primiparous cows fed MON had increased liver triglyceride content compared with CON primiparous cows, and multiparous cows fed MON had decreased liver triglyceride content compared with CON cows. Multiparous cows fed LS with MON had higher liver glycogen content than multiparous cows fed the LS without MON, with no effect of MON treatment for multiparous cows fed HS. There was no effect of starch or MON treatment on liver capacity to oxidize propionate to CO2, and effects of starch on gluconeogenesis were not significant. Cows fed MON tended to have greater capacity to convert propionate to glucose than CON. Supplementation with MON increased the ratio of glucose to CO2, which indicated that cows fed MON had a greater propensity to convert propionate to glucose. Overall, cows fed more propiogenic diets in early lactation (high starch or monensin) exhibited improved energy metabolism during early lactation.

Effect of camelina oil or live yeasts (Saccharomyces cerevisiae) on ruminal methane production, rumen fermentation, and milk fatty acid composition in lactating cows fed grass silage diets

The potential of dietary supplements of 2 live yeast strains (Saccharomyces cerevisiae) or camelina oil to lower ruminal methane (CH4) and carbon dioxide (CO2) production and the associated effects on animal performance, rumen fermentation, rumen microbial populations, nutrient metabolism, and milk fatty acid (FA) composition of cows fed grass silage-based diets were examined. Four Finnish Ayrshire cows (53±7 d in milk) fitted with rumen cannula were used in a 4×4 Latin square with four 42-d periods. Cows received a basal total mixed ration (control treatment) with a 50:50 forage-to-concentrate ratio [on a dry matter (DM) basis] containing grass silage, the same basal total mixed ration supplemented with 1 of 2 live yeasts, A or B, administered directly in the rumen at 10(10) cfu/d (treatments A and B), or supplements of 60g of camelina oil/kg of diet DM that replaced concentrate ingredients in the basal total mixed ration (treatment CO). Relative to the control, treatments A and B had no effects on DM intake, rumen fermentation, ruminal gas production, or apparent total-tract nutrient digestibility. In contrast, treatment CO lowered DM intake and ruminal CH4 and CO2 production, responses associated with numerical nonsignificant decreases in total-tract organic matter digestibility, but no alterations in rumen fermentation characteristics or changes in the total numbers of rumen bacteria, methanogens, protozoa, and fungi. Compared with the control, treatment CO decreased the yields of milk, milk fat, lactose, and protein. Relative to treatment B, treatment CO improved nitrogen utilization due to a lower crude protein intake. Treatment A had no influence on milk FA composition, whereas treatment B increased cis-9 10:1 and decreased 11-cyclohexyl 11:0 and 24:0 concentrations. Treatment CO decreased milk fat 8:0 to 16:0 and total saturated FA, and increased 18:0, 18:1, 18:2, conjugated linoleic acid, 18:3n-3, and trans FA concentrations. Decreases in ruminal CH4 production to treatment CO were related, at least in part to lowered DM intake, whereas treatments had no effect on ruminal CH4 emission intensity (g/kg of digestible organic matter intake or milk yield). Results indicated that live yeasts A and B had no influence on animal performance, ruminal gas production, rumen fermentation, or nutrient utilization in cows fed grass silage-based diets. Dietary supplements of camelina oil decreased ruminal CH4 and CO2 production, but also lowered the yields of milk and milk constituents due to an adverse effect on intake.

Effects of linseed oil or whole linseed supplementation on performance and milk Fatty Acid composition of lactating dairy cows

The objective of this study was to determine the effects of linseed oil or whole linseed supplementation on performance and milk fatty acid composition of lactating dairy cows. Thirty six Holstein Friesian crossbred lactating dairy cows were blocked by milking days first and then stratified random balanced for milk yields and body weight into three groups of 12 cows each. The treatments consisted of basal ration (53:47; forage:concentrate ratio, on a dry matter [DM] basis, respectively) supplemented with 300 g/d of palm oil as a positive control diet (PO), or supplemented with 300 g/d of linseed oil (LSO), or supplemented with 688 g/d of top-dressed whole linseed (WLS). All cows were received ad libitum grass silage and individually fed according to the treatments. The experiment lasted for 10 weeks including the first 2 weeks as the adjustment period, followed by 8 weeks of measurement period. The results showed that LSO and WLS supplementation had no effects on total dry matter intake, milk yield, milk composition, and live weight change; however, the animals fed WLS had higher crude protein (CP) intake than those fed PO and LSO (p<0.05). To compare with the control diet, dairy cow’s diets supplemented with LSO and WLS significantly increased milk concentrations of cis-9, trans-11-conjugated linoleic acid (CLA) (p<0.05) and n-3 fatty acids (FA) (p<0.01), particularly, cis-9,12,15-C18:3, C20:5n-3 and C22:6n-3. Supplementing LSO and WLS induced a reduction of medium chain FA, especially, C12:0-C16:0 FA (p<0.05) while increasing the concentration of milk unsaturated fatty acids (UFA) (p<0.05). Milk FA proportions of n-3 FA remarkably increased whereas the ratio of n-6 to n-3 decreased in the cows supplemented with WLS as compared with those fed the control diet and LSO (p<0.01). In conclusion, supplementing dairy cows’ diet based on grass silage with WLS had no effect on milk yield and milk composition; however, trans-9- C18:1, cis-9, trans-11-CLA, n-3 FA and UFA were increased while saturated FA were decreased by WLS supplementation. Therefore, it is recommended that the addition 300 g/d of oil from whole linseed should be used to lactating dairy cows’ diets.

Comparison of enriched palmitic acid and calcium salts of palm fatty acids distillate fat supplements on milk production and metabolic profiles of high-producing dairy cows

A variable response to fat supplementation has been reported in dairy cows, which may be due to cow production level, environmental conditions, or diet characteristics. In the present experiment, the effect of a high palmitic acid supplement was investigated relative to a conventional Ca salts of palm fatty acids (Ca-FA) supplement in 16 high-producing Holstein cows (46.6±12.4kg of milk/d) arranged in a crossover design with 14-d periods. The experiment was conducted in a non-heat-stress season with 29.5% neutral detergent fiber diets. Treatments were (1) high palmitic acid (PA) supplement fed as free FA [1.9% of dry matter (DM); 84.8% C16:0] and (2) Ca-FA supplement (2.3% of DM; 47.7% C16:0, 35.9% C18:1, and 8.4% C18:2). The PA supplement tended to increase DM intake, and increased the yields of milk and energy-corrected milk. Additionally, PA increased the yields of milk fat, protein, and lactose, whereas milk concentrations of these components were not affected. The yields of milk de novo and 16-C FA were increased by PA compared with Ca-FA (7 and 20%, respectively), whereas the yield of preformed FA was higher in Ca-FA. A reduction in milk fat concentration of de novo and 16-C FA and a marginal elevation in trans-10 C18:1 in Ca-FA is indicative of altered ruminal biohydrogenation and increased risk of milk fat depression. No effect of treatment on plasma insulin was observed. A treatment by time interaction was detected for plasma nonesterified fatty acids (NEFA), which tended to be higher in Ca-FA than in PA before feeding. Overall, the palmitic acid supplement improved production performance in high-producing cows while posing a lower risk for milk fat depression compared with a supplement higher in unsaturated FA.

Invited review: Enteric methane in dairy cattle production: quantifying the opportunities and impact of reducing emissions

Many opportunities exist to reduce enteric methane (CH4) and other greenhouse gas (GHG) emissions per unit of product from ruminant livestock. Research over the past century in genetics, animal health, microbiology, nutrition, and physiology has led to improvements in dairy production where intensively managed farms have GHG emissions as low as 1 kg of CO2 equivalents (CO2e)/kg of energy-corrected milk (ECM), compared with >7 kg of CO2 e/kg of ECM in extensive systems. The objectives of this review are to evaluate options that have been demonstrated to mitigate enteric CH4 emissions per unit of ECM (CH4/ECM) from dairy cattle on a quantitative basis and in a sustained manner and to integrate approaches in genetics, feeding and nutrition, physiology, and health to emphasize why herd productivity, not individual animal productivity, is important to environmental sustainability. A nutrition model based on carbohydrate digestion was used to evaluate the effect of feeding and nutrition strategies on CH4/ECM, and a meta-analysis was conducted to quantify the effects of lipid supplementation on CH4/ECM. A second model combining herd structure dynamics and production level was used to estimate the effect of genetic and management strategies that increase milk yield and reduce culling on CH4/ECM. Some of these approaches discussed require further research, but many could be implemented now. Past efforts in CH4 mitigation have largely focused on identifying and evaluating CH4 mitigation approaches based on nutrition, feeding, and modifications of rumen function. Nutrition and feeding approaches may be able to reduce CH4/ECM by 2.5 to 15%, whereas rumen modifiers have had very little success in terms of sustained CH4 reductions without compromising milk production. More significant reductions of 15 to 30% CH4/ECM can be achieved by combinations of genetic and management approaches, including improvements in heat abatement, disease and fertility management, performance-enhancing technologies, and facility design to increase feed efficiency and life-time productivity of individual animals and herds. Many of the approaches discussed are only partially additive, and all approaches to reducing enteric CH4 emissions should consider the economic impacts on farm profitability and the relationships between enteric CH4 and other GHG.

Effect of growth hormone on the differentiation of bovine preadipocytes into adipocytes and the role of the signal transducer and activator of transcription 5b

We evaluated the effect of GH on the differentiation of primary bovine preadipocytes into adipocytes. Bovine preadipocytes, derived from adipose tissue explants, were induced to differentiate into adipocytes in the presence or absence of recombinant bovine GH. The differentiation status of adipocytes was assessed by Oil Red O staining and by measuring the activity of glycerol-3-phosphate dehydrogenase (G3PDH) and the rate of acetate incorporation. Fewer preadipocytes became adipocytes in the presence of GH than in the absence of GH; adipocytes formed in the presence of GH had lower G3PDH activity and lower rate of acetate incorporation than those formed without GH treatment (P < 0.05). These data suggest an inhibitory effect of GH on the differentiation of bovine preadipocytes into adipocytes. Growth hormone decreased the expression of C/EBPα and PPARγ mRNA in bovine adipocytes (P < 0.05). Because C/EBPα and PPARγ are the master regulators of adipocyte differentiation, this data suggests that GH might inhibit the differentiation of bovine preadipocytes into adipocytes by inhibiting the expression of C/EBPα and/or PPARγ. Because the signal transducer and activator of transcription 5 (STAT5) is a major component of signaling from the GH receptor, we next determined the potential role of STAT5 in GH inhibition of bovine adipocyte differentiation. Overexpression of a constitutively active form of STAT5b (STAT5bCA) in bovine preadipocytes through adenoviral transduction mimicked the effects of GH on the formation of lipid-containing adipocytes, G3PDH activity, and acetate incorporation rate. Overexpression of STAT5bCA was associated with decreased expression of C/EBPα mRNA (P < 0.05) but not that of PPARγ mRNA in bovine adipocytes. These results support a role of STAT5b in mediating GH inhibition of C/EBPα expression but not that of PPARγ expression in bovine preadipocytes. Overall, the present study suggests that GH may inhibit adipose growth in cattle in part by inhibiting adipogenesis and that GH inhibits the differentiation of bovine preadipocytes to adipocytes through STAT5b-dependent inhibition of C/EBPα expression and STAT5b-independent inhibition of PPARγ expression.

Effects of dietary protein levels for gestating gilts on reproductive performance, blood metabolites and milk composition

This experiment was conducted to evaluate the effects of dietary CP levels in gestation under equal lysine content on reproductive performance, blood metabolites and milk composition of gilts. A total of 25 gilts (F1, Yorkshire×Landrace) were allotted to 4 dietary treatments at breeding in a completely randomized design, and fed 1 of 4 experimental diets containing different CP levels (11%, 13%, 15%, or 17%) at 2.0 kg/d throughout the gestation. Body weight of gilts at 24 h postpartum tended to increase linearly (p = 0.09) as dietary CP level increased. In lactation, backfat thickness, ADFI, litter size and weaning to estrus interval (WEI) did not differ among dietary treatments. There were linear increases in litter and piglet weight at 21 d of lactation (p<0.05) and weight gain of litter (p<0.01) and piglet (p<0.05) throughout the lactation as dietary CP level increased. Plasma urea nitrogen levels of gilts in gestation and at 24 h postpartum were linearly elevated as dietary CP level increased (p<0.05). Free fatty acid (FFA) levels in plasma of gestating gilts increased as dietary CP level increased up to 15%, and then decreased with quadratic effects (15 d, p<0.01; 90 d, p<0.05), and a quadratic trend (70 d, p = 0.06). There were no differences in plasma FFA, glucose levels and milk composition in lactation. These results indicate that increasing dietary CP level under equal lysine content in gestation increases BW of gilts and litter performance but does not affect litter size and milk composition. Feeding over 13% CP diet for gestating gilts could be recommended to improve litter growth.

Effects of feeding diets containing highly peroxidized distillers dried grains with solubles and increasing vitamin E levels to wean-finish pigs on growth performance, carcass characteristics, and pork fat composition

Lipid peroxidation in animal feed can negatively affect growth performance and meat quality. Weanling pigs (n = 432; BW = 6.6 ± 0.4 kg) were used to evaluate the effects of feeding peroxidized distillers dried grains with solubles (DDGS) with 3 levels of vitamin E (α-tocopheryl acetate) on growth performance, carcass composition, fatty acid composition of pork fat, and lipid peroxidation in LM. The DDGS source used in this study contained the highest thiobarbituric acid reactive substances (TBARS) value, peroxide value, and total S content (5.2 ng malondialdehyde/mg oil, 84.1 mEq/kg oil, and 0.95%, respectively) among 30 DDGS sources sampled. Pens within blocks were assigned randomly to 1 of 6 diets in a 2 × 3 factorial arrangement of treatments with 8 pens per treatment and 9 pigs per pen. Pigs were fed a corn-soybean meal (CON) or 30% peroxidized DDGS (Ox-DDGS) diets with 3 levels of vitamin E: none supplemented (No-E), NRC (1X-E), or 10X NRC (10X-E). Compared to CON, inclusion of 30% Ox-DDGS in diets reduced (P < 0.001) final BW (110 vs. 107 kg), overall ADG (0.76 vs. 0.74 kg/d), and G:F (0.39 vs. 0.37). Increasing dietary vitamin E concentrations improved G:F (P = 0.03) of pigs fed 10X-E and 1X-E vs. No-E diets (0.39 and 0.39 vs. 0.38, respectively). Hot carcass weight, dressing percentage, backfat depth, and LM area were reduced (P < 0.01) in pigs fed Ox-DDGS compared to CON, but percentage of fat-free carcass lean was not affected. Feeding Ox-DDGS increased (P < 0.001) PUFA concentration, particularly linoleic acid (P < 0.001), and iodine value (P < 0.001) in belly fat and backfat compared to pigs fed CON. Dietary vitamin E levels did not affect fatty acid profiles in belly or back fat. Loin muscle TBARS were measured to determine the lipid peroxidation level in pork loins. Although pigs were fed a Ox-DDGS source in this study, TBARS in LM were similar between Ox-DDGS and CON treatments. There was no interaction between Ox-DDGS and dietary vitamin E concentration in LM TBARS. Alpha-tocopherol concentration in LM was greater (P < 0.001) in 10X-E than No-E or 1X-E dietary treatments. Compared to CON, feeding Ox-DDGS increased α-tocopherol concentration in LM of pigs fed No-E (1.0 vs. 3.1 mg/kg; P = 0.005) but not in those fed 1X-E or 10X-E. These results indicate that feeding diets containing 30% Ox-DDGS to wean-finish pigs may negatively affect growth performance, but supplementation of additional vitamin E in the diet did not counteract these effects.

Estimates of genetic parameters for fatty acids in brisket adipose tissue of Canadian commercial crossbred beef steers

Heritability and genetic and phenotypic correlations between 15 individuals and 10 groups of fatty acids with a concentration greater than 0.5% in the brisket adipose tissue of 223 Angus and Charolais based crossbred commercial steers were estimated using univariate and bivariate animal models. Individual saturated fatty acids were low to moderately heritable, with heritability estimates ranging from 0.05 (C16:0) to 0.31 (C15:0). Individual monounsaturated fatty acids were low to moderately highly heritable ranging from 0.04 (9c C17:1 and 11c C18:1) to 0.51 (9c C14:1). Polyunsaturated fatty acid C18:2n-6 was moderately heritable (0.17). Among groups of fatty acids, heritability estimates ranged from 0.03 for branched chain fatty acid (BCFA) and n-6/n-3 to 0.16 for n-6 and Health Index. A range of low (0.00) to high (1.00) phenotypic and genetic correlations was observed among the 25 fatty acids considered in this study. In general, fatty acids such as conjugated linoleic acid (CLA) and 11t C18:1, with potential health benefits, showed significant antagonistic correlations with unhealthy fatty acids such as C14:0 and C16:0. The results from this study provide insight into the direct genetic control of host genes on fatty acid composition of beef tissues and will facilitate designs of genetic selection and/or genetic based diet management to improve fatty acid composition in beef cattle.

Effects of Clostridium butyricum and Enterococcus faecium on growth performance, lipid metabolism, and cecal microbiota of broiler chickens

To investigate the effects of Clostridium butyricum and Enterococcus faecium on the growth performance, lipid metabolism, and cecal microbiota of broilers, 264 one-day-old male Ross 308 broiler chicks were randomly allocated into four treatments with six replicates in a 2 × 2 factorial arrangement and fed four diets with two levels of C. butyricum (0 or 1 × 10⁹ cfu/kg) and two levels of E. faecium (0 or 2 × 10⁹ cfu/kg) for 42 days. There was no significant interaction between C. butyricum and E. faecium on the growth performance, lipid metabolism, and cecal microbiota of broilers. However, broilers supplemented with E. faecium had lower (P = 0.022) serum leptin level at day 21 and higher (P < 0.001) fatty acid synthase (FAS), malic enzyme (ME), and acetyl-CoA carboxylase (ACC) mRNA levels in the liver at day 42. Supplementation of C. butyricum improved (P < 0.05) the average daily feed intake and average daily gain, increased (P = 0.016) the serum insulin level at 21 days of age, enhanced (P < 0.05) the content of intramuscular fat, activities of FAS in the liver and lipoprotein lipase (LPL) in the breast muscle, mRNA expression of FAS, ME, and ACC in the liver and LPL in the breast muscle at 42 days of age, but reduced (P = 0.030) cecal Bacteroidetes relative abundance at 21 days of age. The results of this study indicate that the increased intramuscular fat content of broilers fed C. butyricum as observed may be the result of enhanced lipogenesis.

Milk fatty acid composition and production performance of Danish Holstein and Danish Jersey cows fed different amounts of linseed and rapeseed

Fat supplements are used in diets for dairy cows to increase energy intake and milk production and the fatty acid composition of the feed affects milk fatty acid composition. A total of 74 Danish Holstein and 41 Danish Jersey cows were divided into 4 groups and the cows within each group were fed a mixed ration supplemented with 0, 3.5, 6.8, or 10.2% of dry matter of a linseed:rapeseed (1:3) mixture during lactation wk 6 to 30. Milk yield, fat, and lactose contents were not affected by treatments for Danish Holsteins, whereas these parameters increased when increased amounts of oilseeds were fed to Danish Jerseys. For both breeds, milk protein content decreased when increased amounts of oilseeds were fed. The milk fatty acid composition showed higher concentrations of saturated fatty acids and lower concentrations of unsaturated fatty acids in milk fat from Danish Jerseys compared with Danish Holsteins. Increased amounts of oilseeds in feed increased milk fat concentration of all C18 fatty acids except C18:2 n-6, whereas the content of C6 to C14, C11 to C17, and in particular, C16, decreased. This effect was more pronounced for Danish Holsteins than for Danish Jerseys. The apparent recovery of C18:2 n-6 and C18:3 n-3 decreased when increased amounts of oilseeds were fed; however, this was most likely due to increased amounts of fatty acid from feed used for other energy demands than milk production. It was concluded that up to 6.8% of oilseed supplementation can be fed without production problems and, in many cases, with positive production responses, including an improved milk fatty acid profile.

Effect of feeding fresh forage and marine algae on the fatty acid composition and oxidation of milk and butter

This study evaluated the effects of feeding fresh forage either as pasture plus a concentrate (PAS) or as a silage-based total mixed ration (TMR), combined with either a ruminally inert lipid supplement high in saturated fatty acids (-) or a ruminally protected microalgae containing 22 g of docosahexaenoic acid (DHA)/100 g of fatty acids (+) on the fatty acid (FA) composition and oxidation of milk and butter. For the 8 mid-lactation Holstein cows in this study, milk yield was not significantly affected by treatment, averaging 32.3 ± 1.28 kg/d. Milk fat content was higher for PAS⁻, averaging 5.05 compared with 4.10 ± 0.17% for the mean of other treatments, and was significantly depressed with microalgae supplementation (3.97 vs. 4.69 ± 0.17%). The saturated fatty acid level in the milk of cows fed TMR⁻ was significantly higher than that of the other treatments (66.9 vs. 61.2 g/100 g of FA). The level of monounsaturated FA was lowered by feeding TMR⁻ (27.4 vs. 32.0 g/100 g of FA), whereas levels of polyunsaturated FA were elevated by feeding PAS+ compared with the mean of the other treatments (6.54 vs. 5.07 g/100 g of FA). Feeding the rumen-protected microalgae increased the DHA content of milk more than 4-fold (0.06 to 0.26 g/100g of FA) with the PAS treatment. The conjugated linoleic acid content of milk was highest for PAS+ compared with the other treatments (4.18 vs. 3.41 g/100g of FA). In general, the fatty acid composition of butter followed that of milk. Overall, feeding the TMR supplemented with the rumen-protected microalgae increased the levels of volatile products of oxidation in milk and butter. No effect of forage type or microalgae supplementation was observed on the oxidative stability or antioxidant capacity of milk, although the oxidative stability of butter exposed to UV was reduced with microalgae supplementation, particularly with TMR, as assessed by using the ferric reducing ability of plasma assay.

Responses to nutrients in farm animals: implications for production and quality

It is well known that any quantitative (energy and protein levels) and qualitative (nature of the diet, nutrient dynamic) changes in the feeding of animals affect metabolism. Energy expenditure and feed efficiency at the whole-body level, nutrient partitioning between and within tissues and organs and, ultimately, tissue and organ characteristics are the major regulated traits with consequences on the quality of the meat and milk produced. Recent progress in biology has brought to light important biological mechanisms which explain these observations: for instance, regulation by the nutrients of gene expression or of key metabolic enzyme activity, interaction and sometimes cross-regulation or competition between nutrients to provide free energy (ATP) to living cells, indirect action of nutrients through a complex hormonal action, and, particularly in herbivores, interactions between trans-fatty acids produced in the rumen and tissue metabolism. One of the main targets of this nutritional regulation is a modification of tissue insulin sensitivity and hence of insulin action. In addition, the nutritional control of mitochondrial activity (and hence of nutrient catabolism) is another major mechanism by which nutrients may affect body composition and tissue characteristics. These regulations are of great importance in the most metabolically active tissues (the digestive tract and the liver) and may have undesirable (i.e. diabetes and obesity in humans) or desirable consequences (such as the production of fatty liver by ducks and geese, and the production of fatty and hence tasty meat or milk with an adapted fatty acid profile).

Nutritional Influences on Skatole Formation and Skatole Metabolism in the Pig

Skatole is a tryptophan (TRP) metabolite with fecal odor. Together with the testicular steroid androstenone it is regarded as a main determinant of boar taint, even if elevated concentrations of skatole occur occasionally in gilts and barrows. Skatole concentrations in adipose tissue result from a complex process, which includes the availability of TRP and the presence of specialized bacteria in the gut in need of TRP for energy production, as well as absorption, transport and accumulation of skatole in adipose tissue. Several steps of this process are influenced by diet and specific feed compounds. In the present paper the current knowledge about physiological mechanisms of skatole dynamics is summarized. Additionally mechanisms are discussed, by which effective feeding strategies and feed additives exert their influence in the prevention of high skatole concentrations in adipose pig tissue. It was concluded that the most effective measures are those which influence several steps of skatole formation. Despite the numerous studies carried out in the field of skatole physiology, interesting aspects still need clarification, such as the effect of adipose tissue turnover. Reliable control of skatole accretion in fat of boars is one of the main prerequisites for pork production with entire males.

Effect of plant oils and camelina expeller on milk fatty acid composition in lactating cows fed diets based on red clover silage

Five multiparous Finnish Ayrshire cows fed red clover silage-based diets were used in a 5 × 5 Latin square with 21-d experimental periods to evaluate the effects of various plant oils or camelina expeller on animal performance and milk fatty acid composition. Treatments consisted of 5 concentrate supplements containing no additional lipid (control), or 29 g/kg of lipid from rapeseed oil (RO), sunflower-seed oil (SFO), camelina-seed oil (CO), or camelina expeller (CE). Cows were offered red clover silage ad libitum and 12kg/d of experimental concentrates. Treatments had no effect on silage or total dry matter intake, whole-tract digestibility coefficients, milk yield, or milk composition. Plant oils in the diet decreased short- and medium-chain saturated fatty acid (6:0-16:0) concentrations, including odd- and branched-chain fatty acids and enhanced milk fat 18:0 and 18-carbon unsaturated fatty acid content. Increases in the relative proportions of cis 18:1, trans 18:1, nonconjugated 18:2, conjugated linoleic acid (CLA), and polyunsaturated fatty acids in milk fat were dependent on the fatty acid composition of oils in the diet. Rapeseed oil in the diet was associated with the enrichment of trans 18:1 (Δ4, 6, 7, 8, and 9), cis-9 18:1, and trans-7,cis-9 CLA, SFO resulted in the highest concentrations of trans-5, trans-10, and trans-11 18:1, Δ9,11 CLA, Δ10,12 CLA, and 18:2n-6, whereas CO enhanced trans-13-16 18:1, Δ11,15 18:2, Δ12,15 18:2, cis-9,trans-13 18:2, Δ11,13 CLA, Δ12,14 CLA, Δ13,15 CLA, Δ9,11,15 18:3, and 18:3n-3. Relative to CO, CE resulted in lower 18:0 and cis-9 18:1 concentrations and higher proportions of trans-10 18:1, trans-11 18:1, cis-9,trans-11 CLA, cis-9,trans-13 18:2, and trans-11,cis-15 18:2. Comparison of milk fat composition responses to CO and CE suggest that the biohydrogenation of unsaturated 18-carbon fatty acids to 18:0 in the rumen was less complete for camelina lipid supplied as an expeller than as free oil. In conclusion, moderate amounts of plant oils in diets based on red clover silage had no adverse effects on silage dry matter intake, nutrient digestion, or milk production, but altered milk fat composition, with changes characterized as a decrease in saturated fatty acids, an increase in trans fatty acids, and enrichment of specific unsaturated fatty acids depending on the fatty acid composition of lipid supplements.

Effects of flushing and hormonal treatment on reproductive performance of Iranian Markhoz goats

Forty-eight Iranian Markhoz goats were allocated to six groups (n = 8) to study the effect of flushing and hormonal treatments on reproductive performance. Treatments were divided into two categories including, hormonal treatments and flushing. The goats in each group were fed the same basal ration and received one of the following treatments: Groups A and B--injection of GnRH and equine chorionic gonadotropin (eCG) respectively; Groups C, D and E--a supplement of barley grain, soybean oil and sunflower oil in flushing diets, respectively, were offered and Group F--control (only received basal diet). In the flushing treatments, only the source of energy was different between rations. Both hormonal treatments and flushing treatments improved fertility and kidding rates. Treatment B with 16 and control with seven kids represented the highest and the lowest number of progeny respectively. Among flushing treatments, group C resulted in the highest number of kids being 15. Oestrogen levels in follicular phase increased with the injection of eCG and consumption of barley grain. GnRH injection and consumption of oil sources in the diet increased blood progesterone levels during ovulation and post-ovulation periods. Under current market conditions, using hormone or flushing can be profitable for Markhoz goats farmers.

Digestion, milk production and milk fatty acid profile of dairy cows fed flax hulls and infused with flax oil in the abomasum

Flax hull, a co-product obtained from flax processing, is a rich source of n-3 fatty acids (FA) but there is little information on digestion of flax hull based diets and nutritive value of flax hull for dairy production. Flax oil is rich in α-linolenic acid (LNA) and rumen bypass of flax oil contributes to increase n-3 FA proportions in milk. Therefore, the main objective of the experiment was to determine the effects of abomasal infusion of increasing amounts of flax oil on apparent digestibility, dry matter (DM) intake, milk production, milk composition, and milk FA profile with emphasis on the proportion of LNA when cows were supplemented or not with another source of LNA such as flax hull. Six multiparous Holstein cows averaging 650±36 kg body weight and 95±20 d in milk were assigned to a 6×6 Latin square design (21-d experimental periods) with a 2×3 factorial arrangement of treatments. Treatments were: 1) control, neither flax hull nor flax oil (CON), 2) diet containing (DM basis) 15·9% flaxseed hull (FHU); 3) CON with abomasal infusion of 250 g/d flax oil; 4) CON with abomasal infusion of 500 g/d flax oil; 5) FHU with abomasal infusion of 250 g/d flax oil; 6) FHU with abomasal infusion of 500 g/d flax oil. Infusion of flax oil in the abomasum resulted in a more pronounce decrease in DM intake for cows fed the CON diets than for those fed the FHU diets. Abomasal infusion of flax oil had little effect on digestibility and FHU supplementation increased digestibility of DM and crude protein. Milk yield was not changed by abomasal infusion of flax oil where it was decreased with FHU supplementation. Cows fed FHU had higher proportions of 18:0, cis9-18:1, trans dienes, trans monoenes and total trans in milk fat than those fed CON. Proportion of LNA was similar in milk fat of cows infused with 250 and 500 g/d flax oil in the abomasum. Independently of the basal diet, abomasal infusion of flax oil resulted in the lowest n-6:n-3 FA ratio in milk fat, suggesting that the most important factor for modification of milk FA profile was the amount of n-3 FA bypassing the rumen and not the amount of flax hull fed to dairy cows. Moreover, these data suggest that there is no advantage to supply more than 250 g/d of flax oil in the abomasum to increase the proportion of LNA in milk fat.

Comparative Approach of the de novo Fatty Acid Synthesis (Lipogenesis) between Ruminant and Non Ruminant Mammalian Species: From Biochemical Level to the Main Regulatory Lipogenic Genes

Over the second half of 20^th century much research on lipogenesis has been conducted, especially focused on increasing the production efficiency and improving the quality of animal derived products. However, many diferences are observed in the physiology of lipogenesis between species. Recently, many studies have also elucidated the involvement of numerous genes in this procedure, highlighting diferences not only at physiology but also at the molecular level. The main scope of this review is to point out the major differences between ruminant and non ruminant species, that are observed in key regulatory genes involved in lipogenesis. Human is used as a central reference and according to the findinggs, main differences are analysed. These findings could serve not only as basis for understanding the main physiology of lipogenesis and further basic research, but also as a basis for any animal scientist to develop new concepts and methods for use in improving animal production and modern genetic improvement.

A novel single nucleotide polymorphism in exon 7 of LPL gene and its association with carcass traits and visceral fat deposition in yak (Bos grunniens) steers

Lipoprotein lipase (LPL) is considered as a key enzyme in the lipid deposition and metabolism in tissues. It is assumed to be a major candidate gene for genetic markers in lipid deposition. Therefore, the polymorphisms of the LPL gene and associations with carcass traits and viscera fat content were examined in 398 individuals from five yak (Bos grunniens) breeds using PCR-SSCP analysis and DNA sequencing. A novel nucleotide polymorphism (SNP)-C→T (nt19913) was identified located in exon 7 in the coding region of the LPL gene, which replacement was responsible for a Phe-to-Ser substitution at amino acid. Two alleles (A and B) and three genotypes designed as AA, AB and BB were detected in the PCR products. The frequencies of allele A were 0.7928, 0.7421, 0.7357, 0.6900 and 0.7083 for Tianzhu white yak (WY), Gannan yak (GY), Qinghai-Plateau yak (PY), Xinjiang yak (XY) and Datong yak (DY), respectively. The SNP loci was in Hardy-Weinberg equilibrium in five yak populations (P>0.05). Polymorphism of LPL gene was shown to be associated with carcass traits and lipid deposition. Least squares analysis revealed that there was a significant effect on live-weight (LW) (P<0.01), average daily weight gain (ADG) and carcass weight (P<0.05). Individuals with genotype BB had lower mean values than those with genotype AA and AB for loin eye area and viscera fat weight (% of LW) in 25-36 months (P<0.05). The results indicated that LPL gene is a strong candidate gene that affects carcass traits and fat deposition in yak.

Effects of feeding diets containing increasing content of corn distillers dried grains with solubles to grower-finisher pigs on growth performance, carcass composition, and pork fat quality

Crossbred pigs (n = 512) with an average initial BW of 22.1 +/- 0.54 kg were used to evaluate growth performance, carcass characteristics, and pork fat quality of grower-finisher pigs fed corn-soybean meal diets containing increasing content of distillers dried grains with solubles (DDGS). One of 4 dietary treatments was randomly assigned to each pen within sex. Dietary treatment and sex were the main factors in a 3-phase feeding program (BW = 22 to 53 kg, 53 to 85 kg, and 85 to 115 kg). Dietary treatments consisted of a corn-soybean meal control, or a corn-soybean meal diet containing 10, 20, or 30% DDGS. Overall, increasing the dietary DDGS content had no effect on ADG (P = 0.74), but ADFI was linearly reduced and G:F was linearly increased (P < 0.01). Dressing percentage, LM marbling and firmness, and belly firmness were linearly reduced (P < 0.01), but percentage of fat-free lean was linearly increased (P < 0.05) with increasing dietary DDGS. Subjective LM color score (P = 0.65), drip loss (P = 0.37), and ultimate pH of LM (P = 0.21) were not influenced by dietary DDGS. Japanese color scores for backfat (P = 0.41) and belly fat (P = 0.85) were similar among dietary treatments (P = 0.41). Feeding an increasing content of DDGS linearly increased (P < 0.05) PUFA concentration, particularly linoleic acid (C18:2), in belly fat, backfat, and LM intramuscular fat, but the increase in LM intramuscular fat was smaller in magnitude (P < 0.05) than in backfat and belly fat. Pigs fed an increasing content of DDGS had a linear increase (P < 0.05) in the iodine value of backfat, belly fat, and LM intramuscular fat of 58.4 to 72.4, 61.5 to 72.3, and 54.8 to 57.7, respectively. Oxidation of LM intramuscular fat measured on d 0, 14, 21, and 28 of storage was not affected by dietary treatment. Taste tests for LM showed no effects of diet on flavor, off-flavor (P = 0.36), tenderness (P = 0.66), juiciness (P = 0.58), and overall acceptability (P = 0.52) scores. Similarly, bacon flavor (P = 0.88), off-flavor, crispiness, and overall liking scores were not affected by increasing dietary DDGS, but bacon fattiness (P < 0.01) and tenderness (P < 0.05) scores were linearly reduced. These results showed no negative effects on growth performance or dressing percentage when growing-finishing pigs were fed diets containing up to 30% DDGS, but fat quality may not meet the standards of all pork processors when feeding diets containing more than 20% DDGS.

Whole intact rapeseeds or sunflower oil in high-forage or high-concentrate diets affects milk yield, milk composition, and mammary gene expression profile in goats

This study aimed to ascertain the response of goat mammary metabolic pathways to concentrate and lipid feeding in relation to milk fatty acid (FA) composition and secretion. Sixteen midlactation multiparous goats received diets differing in forage-to-concentrate ratio [high forage (HF) 64:36, and low forage (LF) 43:57] supplemented or not with lipids [HF with 130 g/d of oil from whole intact rapeseeds (RS) and LF with 130 g/d of sunflower oil (SO)] in a 4 x 4 Latin square design. Milk yield, milk composition, FA profile, and FA secretion were measured, as well as the expression profiles of key genes in mammary metabolism and of 8,382 genes, using a bovine oligonucleotide microarray. After 3 wk of treatment, milk, lactose, and protein yields were lower with HF-RS than with the other diets, whereas treatment had no effect on milk protein content. Milk fat content was higher with the HF-RS and LF-SO diets than with the HF and LF diets, and SO supplementation increased milk fat yield compared with the LF diet. Decreasing the forage-to-concentrate ratio from 64:36 to 43:57 had a limited effect on goat milk FA concentrations and secretions. Supplementing the LF diet with SO changed almost all the FA concentrations, including decreases in medium-chain saturated FA and large increases in trans C18:1 and C18:2 isomers (particularly trans-11 C18:1 and cis-9, trans-11 conjugated linoleic acid), without significant changes in C18:0 and cis-9 C18:1, whereas supplementing the HF diet with RS led to a strong decrease in short- and medium-chain saturated FA and a very strong increase in C18:0 and cis-9 C18:1, without significant changes in trans C18:1 and conjugated linoleic acid. Despite the decreases in milk lactose and protein yields observed with HF-RS, and despite the decrease in milk medium-chain FA and the increase in C18 FA secretion with RS or SO supplementation, none of the dietary treatments had any effect on mammary mRNA expression of the key genes involved in lactose (e.g., alpha-lactalbumin), protein (e.g., beta-casein), and lipid metabolism (e.g., lipoprotein lipase) after 3 wk of treatment. In addition, transcriptome analysis did not provide evidence of treatments inducing significant changes in the expression of specific genes in the mammary gland. However, 2-way hierarchical clustering analysis highlighted different global mammary expression profiles between diets, showing that the gene expression profiles corresponding to the same diet were gathered by common groups of genes. This experiment suggests that after 3 wk of dietary treatment, other factors, such as substrate availability for mammary metabolism, could play an important role in contributing to milk FA responses to changes in diet composition in the goat.