Acetyl-CoA carboxylase of sheep adipose tissue: problems of the assay and adaptation during fetal development

The rate of fatty acid synthesis of perirenal adipose tissue of fetal lambs decreased by 90% during the last month of gestation. There was also a 90% decrease in the activity of fatty acid synthetase during this period, but the activity of this enzyme exceeded lipogenic flux by a factor of 10. The activity of acetyl CoA carboxylase in the active state (initial activity) was very similar to the lipogenic flux in adipose tissue from lambs at 120 d of gestation; although activity decreased towards term, the decline was insufficient to account for the fall in rate of fatty acid synthesis. The study also shows that assay of acetyl CoA carboxylase in the active state of ovine adipose tissue and of caprine mammary gland requires the presence of citrate, thus differing from that for rat adipose tissue. Evidence that pyruvate carboxylase can interfere in the assay of acetyl CoA carboxylase also is presented.     

Depot specific endocrine control of fatty acid synthesis in adipose tissues of foetal lambs

Chronic endocrine control of fatty acid synthesis in perirenal and subcutaneous adipose tissues of foetal lambs has been investigated. Maintenance of explants of subcutaneous adipose tissue in culture for 48 hr with insulin and dexamethasone (a glucocorticoid analogue), either singly or in combination showed that the two acted synergistically to increase the rate of fatty acid synthesis. Growth hormone inhibited the ability of insulin plus dexamethasone to increase the rate of fatty acid synthesis in explants of subcutaneous adipose tissue. In contrast neither insulin nor dexamethasone either singly or together increased the rate of fatty acid synthesis in perirenal adipose tissue; growth hormone also had no effect on the rate of fatty acid synthesis in this depot. These studies show that fatty acid synthesis is under distinct endocrine control in subcutaneous and perirenal adipose tissues in foetal lambs.     

Effect of dietary mono- and polyunsaturated fatty acids on the fatty acid composition of pigs' adipose tissues.

In two experiments with growing-finishing pigs six different dietary fats were added to a conventional diet (control--C) to study the effects of dietary monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA) on the fatty acid composition of backfat and kidney fat at similar amounts of double bonds in feed (Exp. 1:7% pork fat--PF, 4.95% olive oil--OO, 3.17% soybean oil--SO) or a constant amount of 5% of processed fats (Exp. 2: partially hydrogenated fat--SAT, fractionated pork fats: olein--OLE, stearin--STE). Compared with the control, PUFA were only slightly increased in backfat of pigs fed PF, OLE, STE or OO, although dietary PUFA intake was up to 70% higher. With SO PUFA were significantly increased in adipose tissues, predominantly at the expense of MUFA. Consequently, a non-linear relationship was found between PUFA intake and proportion in backfat. MUFA were incorporated at the expense of SFA, therefore, adipose tissues of OO fed animals were lowest in SFA. Despite comparable amounts of double bonds in feed (Exp. 1), the degree of unsaturation measured as fat score (sum of double bonds) was in the order SO > OO > PF > C. In contrast, the proportion of SFA was C > PF = SO > OO. Regarding the decisive role of SFA for fat consistency it may be concluded that MUFA should also be considered in feeding recommendations for pigs. Furthermore, in case of a high dietary supply of MUFA, a simple index of double bonds might not be sufficiently conclusive to judge pig fat quality.     

Decrease in stearic acid proportions in adipose tissues and liver lipids in fatty liver of dairy cows

Samples of liver and perirenal, mesenteric and subcutaneous fat were collected from 16 sick necropsied dairy cows to evaluate the fatty acid profiles in the hepatic and adipose tissues associated with advanced fatty liver or hepatic lipidosis. Hepatic triglyceride and eight fatty acids were measured in the hepatic and adipose tissues. Six cows had more than 3% triglyceride on fresh weight in their livers and were classified as having fatty liver. Stearic and linoleic acid proportions in the liver decreased markedly with increased hepatic triglyceride levels, while the proportion of palmitic and oleic acids increased. The most striking fluctuations in hepatic lipidosis were manifested as decreased stearic acid in the adipose tissues including subcutaneous fat with the trend of decreasing stearic acid. Palmitic acid was elevated in hepatic and perirenal fat in fatty liver cows. In instances of advanced hepatic lipidosis, palmitoleic acid increased in only subcutaneous fat and not in perirenal or mesenteric fat. In addition to the proportions of hepatic fatty acids in fatty liver, this study also clarified the fluctuations observed in the profiles of fatty acids of the adipose tissues in cows with advanced hepatic lipidosis, particularly the decline in the proportions of stearic acid.     

α-短链脂肪酸单甘油酯在白羽肉鸡的饲养效果观察

该研究对α-短链脂肪酸单甘油酯在白羽肉鸡中的饲养效果进行观察,结果表明FraC34在白羽肉鸡饲养环节中全程添加具有明显改善白羽肉鸡生产性能的作用,可作为促生长剂替代抗生素饲料添加剂。     

Effect of feeding rumen-protected conjugated linoleic acid on carcass characteristics and fatty acid composition of sheep tissues

Two experiments were conducted to determine the effectiveness of a rumen-protected CLA (pCLA) supplement and the impact of feeding this pCLA on carcass characteristics and tissue fatty acid composition of lambs. In Exp. 1, a CLA-80 preparation (80% pure CLA; contained similar proportions of cis-9, trans-11, and trans-10, cis-12 CLA), protected against rumen degradation, was fed to sheep, and the proportion of CLA reaching the duodenum was determined. A 3 x 3 Latin square design was used with 3 diets (1.4 kg of concentrate-based control diet, the same control diet plus 22 g of CLA-80, or the same control diet plus 110 g of pCLA/d), 3 feeding periods, and 3 rumen and duodenally cannulated sheep (Mule x Charolais males, 10 mo of age, BW 55.3 +/- 1.8 kg). After 7 d of feeding, sheep were ruminally infused with chromium EDTA and Yb acetate for 7 d, after which samples of duodenal digesta were collected every 6 h for 48 h to determine the quantity of CLA reaching the small intestine each day. The amounts of CLA cis-9, trans-11 and trans-10, cis-12, and combined isomers, flowing through the duodenum each day were greater (P = 0.01) in sheep fed pCLA. Approximately 65% of the pCLA avoided rumen biohydrogenation, with the ratio of the 2 main isomers remaining similar. In Exp. 2, 36 Mule x Charolais ewe lambs (approximately 13-wk old, average initial BW 29.3 kg) were fed 3 levels of the pCLA or Megalac, which were fed to provide an equivalent energy content at each pCLA level. Lambs were randomly assigned to 1 of 7 treatment groups, which were fed for 10 wk to achieve a growth rate of 180 g/d. Treatments included the basal diet and the basal diet plus 25, 50, or 100 g of pCLA/kg of diet or the equivalent amount of Megalac. In liver (P < 0.001) and all adipose tissue depots studied, the proportions of both CLA isomers increased (P = 0.02) with the amount of pCLA fed but were not altered with increasing of Megalac. Although there was no effect of treatment on cis-9, trans-11 CLA content, accumulation (P < 0.001) in the LM with increasing of pCLA supplementation was observed for the trans-10, cis-12 isomer. Although tissues had been enriched with CLA, there was no evidence of a reduction in adipose tissue or an increase in muscle mass in these sheep. However, an effect of pCLA on tissue fatty acid composition was consistent with an inhibition of stearoyl-CoA desaturase.     

Effects of supplemental rumen-protected conjugated linoleic acid or corn oil on fatty acid composition of adipose tissues in beef cattle

Thirty-six Angus x Hereford heifers (365 +/- 60 kg) were used to determine the effects of supplemental dietary lipid sources on fatty acid composition of i.m., perianal (p.a.), and s.c. lipid depots. Lipid was supplied to diets as either corn oil or a rumen-protected conjugated linoleic acid (CLA) salt for two specific treatment periods of either the final 32 or 60 d on feed. Following an initial 56-d feeding period, heifers were fed one of three dietary treatments (DM basis): 1) basal diet containing 88% concentrate and 12% grass hay (CON), 2) basal diet plus 4% corn oil (OIL), or 3) basal diet plus 2% rumen-protected CLA salt (RPCLA) containing 31% CLA. The trans-10, cis-12 CLA concentration was greatest (P < 0.05) for heifers fed RPCLA and OIL diets and least (P < 0.05) for CON, regardless of time on dietary treatment. Heifers fed supplemental RPCLA had greater (P < 0.05) total CLA content than either CON- or OIL-fed heifers. Adipose tissue concentration of trans-11 vaccenic acid (TVA) was less (P < 0.05) for CON than OIL or RPCLA, which did not differ (P > 0.05). Percentages of C18:1 trans-10 were least (P < 0.05) in i.m. lipid compared with p.a. and s.c., which did not differ (P > 0.05). Following 60 d of lipid supplementation, heifers fed OIL and RPCLA had lower (P < 0.05) concentrations of oleic acid and total monounsaturated fatty acids (MUFA) compared with CON. The ratio of cis-9, trans-11 CLA:TVA was higher (P < 0.05) for heifers fed 60 vs. 32 d, but did not differ (P > 0.05) between adipose depots. Feeding OIL increased (P < 0.05) adipose concentration of C18:2 fatty acid, whereas feeding RPCLA increased (P < 0.05) total CLA isomers by 22%. Intramuscular lipid contained the lowest (P < 0.05) percentage of cis-9, trans-11 CLA, total CLA, C18:1 cis-9, C18:1 trans-10, and TVA. Total CLA and cis-9, trans-11 CLA isomers were increased (P < 0.05) in p.a. and s.c. adipose depots, whereas i.m. adipose tissue contained increased (P < 0.05) amounts of total PUFA. Results from this study indicate that short-term lipid supplementation to feedlot cattle can increase adipose tissue CLA concentrations, but only marginally (8.3 to 17.5%). Moreover, observed decreases in oleic acid and total MUFA concentrations of adipose tissues from heifers fed rumen-protected CLA or corn oil suggest that lipid supplementation may decrease delta9 desaturase activity in adipose tissues, which in turn would lower the conversion of TVA to cis-9, trans-11 CLA isomer.     

Growth, carcass traits, and fatty acid profiles of adipose tissues from steers fed whole cottonseed

To investigate the impact of dietary whole cottonseed (WCS) level on fatty acid composition, growth, and carcass traits, 45 Hereford steers were assigned to diets containing 0, 15, or 30% dietary WCS. The 15 and 30% WCS contributed an estimated 3.3 and 6.6% additional lipid, respectively, to the diets. After being fed for 54 d, all animals were weighed and slaughtered, and carcass measurements were obtained. There were no differences (P greater than .05) among dietary treatment groups in live weight or ADG for the 54-d feeding period. Control steers had larger (P less than .05) longissimus muscle areas than steers fed 30% WCS, which accounted for the advantage in yield grade (P less than .05) exhibited by the control group. Feeding of 30% WCS resulted in minor increases in linoleic and total polyunsaturated fatty acid content of perinephric fat expressed in both normalized (area percentage) and gravimetric (g/100 g of fresh tissue) formats. There were no significant differences in the monounsaturated or saturated fatty acid content of adipose tissues from animals fed the different diets. Subcutaneous adipose tissue samples were higher (P less than .01) in total unsaturates but had lower (P less than .05) proportions of C18:0 and C18:1 than perinephric samples. Feeding WCS at the levels reported herein only had minor effects on fatty acid composition of beef adipose tissues.     

Relationship between adipose maturity and fatty acid composition in various adipose tissues of Japanese Black,Holstein and Crossbred (F1) steers

The amount of monounsaturated fatty acid (MUFA) is intimately related to adipose softness, melting point (MP) and flavor in beef. Stearoyl‐CoA desaturase (SCD) is a main gene involved in MUFA synthesis. Mature adipose tends to be highly saturated, whereas immature or maturing adipose is highly unsaturated when chronologically based, so the degree of non‐saturation can be an index of adipose maturity. In this study, three different adipose tissues (coelomic (CL), perirenal (PR), and subcutaneous (SC)) from three beef breeds with differing slaughter ages (Japanese Black (29.5 months), Holstein (20.1 month), and F1 crossbreed (25.6 months)) were examined to: (i) determine adipose maturity level as indexed by MUFA %; and (ii) determine SCD and other lipogenic gene messenger RNA (mRNA) expression levels in relation to unsaturated fatty acid content. Fatty acid composition was significantly different between adipose tissues (P < 0.05). MUFA amount was high in the following order: SC > CL > PR. This pattern corresponded to SCD mRNA expression profile showing higher expression in SC than CL and PR. However, Japanese black cattle are an exception with CL adipose containing similar UFA % as SC adipose, yet having the lowest SCD mRNA expression level among all adipose tissues tested. Therefore, SCD mRNA expression and MUFA % appear to be directly related; however, differences in SCD mRNA expression among three adipose tissues may reflect differences in the fat development characteristics affected by chronological age of the cattle breeds.     

The effect of feeding a sub-optimum level of lysine to female chicks on the amino acid content of selected tissues and organs

The amino acid content of the liver, brain, serum and leg muscle of broiler breeder female chicks was not influenced appreciably at 4 and 8 weeks of age by feeding a diet containing sub‐optimum levels of lysine. The feeding of the low‐lysine diet produced a slight effect on the amino acid content of the breast muscle and a decided effect on the amino acid content of the skin and bone marrow at 4 and 8 weeks of age. The amino acid content of the heart tissue from chicks which received the 0.53% lysine diet was higher at 4 weeks of age. No explanation for this observation can be offered. The more decided changes were produced in the bone marrow of the chicks fed the low‐lysine diet at 4 and 8 weeks of age.

There is a possibility that feeding the low‐lysine diet had an effect on protein synthesis in the bone marrow. Chicks fed the low‐lysine diet had apparently overcome the lysine deficiency in the synthesis of protein of the bone marrow at the end of the 12th week.     

A new system for the protein feeding of ruminants: The PDI system

To replace the digestible crude protein system (DCP) a new system is proposed which is named the PDI system (Protéines Digestibles dans l'Intestin grêle). It estimates the quantity of amino nitrogen N × 6.25 absorbed in the small intestine from the dietary protein which has escaped fermentation in the rumen, and the microbial protein arising from that fermentation.The extent of N degradation in the rumen and the microbial protein yield (135 g/kg of digestible organic matter intake) were obtained using an equation describing the flow of non-ammonia N entering the duodenum. The true digestibility of microbial true protein (80% of microbial crude protein) was considered equal to 0.70 and that of dietary protein was calculated from nitrogen and organic matter digestibilities of each feed.Two PDI values are ascribed to each feed: one (PDIN) calculated from both its non-degradable N and degradable N contents and the other (PDIE) from both its non-degradable N contents and its content of rumen available energy (in fact its digestible organic matter content). When calculating the PDI value of a diet, the PDIN and PDIE values of the different ingredients are summed separately: the PDI value of the diet is the lower of the two values.The PDI requirements of animals have not been measured previously. They were calculated from nitrogen balance trials on non-producing animals and from feeding trials on producing animals. The mean efficiency of PDI utilization was found to be 0.67 for milk production in cows, 0.60 for body gain in cattle and 0.60 for pregnancy in sheep. These values have also been used with animals of other species.The advantages of the PDI system over the DCP system, as well as its shortcomings, are discussed. It is compared with alternative systems which have been proposed recently in other countries.     

脂肪酸的吸收与脂肪酸结合蛋白

脂肪酸在动物体内的消化吸收是一个非常复杂的过程,需要通过小肠上皮细胞的消化、吸收和转运。脂肪酸吸收研究方法主要分为体内法和体外法。脂肪酸的吸收主要发生在小肠的前2/3部分,而小肠上皮细胞内含有脂肪酸结合蛋白对脂肪酸的吸收以及脂肪酸在细胞内的转运具有极其重要的作用。文中主要综述了脂肪酸的吸收及脂肪酸结合蛋白的相关功能,着重概括了小肠内表达的I-FABP、L-FABP两种蛋白。     

Effect of dietary energy supply and fat source on the fatty acid pattern of adipose and lean tissues and lipogenesis in the pig

Forty Large White barrows were used to determine whether the effects of dietary fat source (tallow or soy oil at 5% of the diet) on lipogenesis and fatty acid profile of porcine adipose and lean tissue were dependent on dietary digestible energy density (8.8 vs 14.0 MJ DE/kg). Barrows were allocated to one of four groups and offered a fixed amount of feed (170 g x BW0.569/d) from 27 to 105 kg BW. The fatty acid composition of the backfat layers (BF), omental fat (OF), and i.m. adipose tissue of longissimus muscle as well as the activity of lipogenic enzymes of the adipose tissues were determined. Growth performance and carcass characteristics were affected by the dietary energy level (P < 0.01) but not by fat source. In accordance with the lower carcass fat deposition, the activity of lipogenic enzymes were decreased in the low-energy groups (P < 0.01). Within dietary energy level, inclusion of soy oil resulted in increased proportion of PUFA that was compensated by decreased saturated (SFA) and monounsaturated fatty acid (MUFA) proportions (P < 0.01). The SFA changes accounted for 23 (BF) and 24% (OF) of the PUFA changes in the high-energy and 31 (BF) and 39% (OF) in the low-energy diets. The differences in the fatty acid proportions between the soy oil and tallow group were more pronounced in the low-energy groups (fat source x energy density interactions: P < 0.01). Pigs fed the soy oil, low-energy diet had decreased SFA (BF: 28%; OF: 30%) and MUFA (BF: 13%; OF: 19%) concentration, whereas PUFA concentration was increased (BF: 59%; OF: 88%) compared with pigs fed the soy oil, high-energy diet. However, in the tallow groups, pigs fed the low-energy diets had slightly decreased SFA (BF: 14%; OF: 12%) and relatively constant MUFA (BF: 3%; OF: 1%), whereas PUFA concentration increased (BF: 39%; OF: 62%) relative to pigs fed the tallow high-energy diet. Lipid content of the i.m. adipose tissue was decreased in the low-energy groups (P < 0.05). Contrary to what was observed in the adipose tissues, increased PUFA concentration in the neutral and polar lipid fractions of the longissimus muscle was predominantly compensated by reduced MUFA deposition. In the polar lipid fraction, the proportions of both SFA and MUFA were decreased by the low-energy diet. Thus, the extent to which tissue concentration of fatty acids are altered from dietary fats differing in the degree of unsaturation depends on the dietary energy level.     

Effect of high temperature and feeding level on energy utilization in piglets

The effect of temperature (23 or 33 degrees C) and feeding level on components of energy balance was studied in seven groups of individually reared Piétrain x (Landrace x Large White) littermate piglets. Within each litter, one pig was reared at 23 degrees C and given a predefined feeding level close to ad libitum (23AL pigs), one was reared at 33 degrees C and also fed close to ad libitum (33AL), and one was reared at 23 degrees C and pair-fed to the 33AL pig (23PF). Piglets of one litter were acclimated during 2 to 4 wk to their experimental temperature in temperature-controlled rooms before being transferred (one per week) to a respiration chamber for measurement of nitrogen and energy balances. The average initial BW was 22.4 kg. The data on O2 consumption, CO2 production, and physical activity were collected over seven consecutive days and used to calculate total heat production (HPtot) and its components: fasting heat production (FHP), heat production due to physical activity (HPact), and thermic effect of feed (TEF). A preliminary trial was conducted in which heat production was measured in three piglets according to a Latin square design at 23, 25, and 27 degrees C. Total heat production was, but activity-free heat production was not, affected by temperature, and no firm conclusions could be drawn as to whether 23 degrees C was within the thermoneutral zone of fed piglets. In Trial 2, the combination of increased temperature and reduced feed intake resulted in a 20% lesser heat production in 33AL than in 23AL pigs. This was due to a reduction in both TEF (-39%) and FHP (0.642 vs 0.808 MJ x d(-1) x kg BW-0.60). Despite the shorter duration of standing activity, HPact was slightly higher at 33 degrees C, probably due to hyperventilation at this temperature. With similar feeding levels (23PF vs 33AL), HPtot and activity-free heat production were less at 33 degrees C and energy retention as protein (+6%) and fat (+31%) was increased. Because HPact was similar for both treatments, the greater energy retention for 33AL seemed to be due to a greater utilization of feed energy or to a reduced maintenance requirement (i.e., reduced FHP). However, the type of stress imposed on 23PF and 33AL pigs was different and may have affected energy metabolism. The results suggest that the reduction in heat production of piglets at high ambient temperatures is caused by a reduction in voluntary feed intake and differences in energetic efficiency. The mechanisms for the lesser efficiency at 23 degrees C compared to 33 degrees C (at the same level of feed intake) remain unclear.     

Effect of dietary protein quality and essential fatty acids on fatty acid composition in the liver and adipose tissue after rapid weight loss in overweight cats

OBJECTIVE: To examine effects of dietary protein quality (casein [CA] vs corn gluten [CG]) and dietary lipids (corn oil [CO] vs oil blend [OB] rich in long-chain polyunsaturated fatty acids [LCPUFAs]) on fatty acid composition in liver and adipose tissue after weight loss in overweight cats. ANIMALS: 24 ovariohysterectomized adult cats. PROCEDURE: Cats were allowed ad libitum access to a high-quality diet until they weighed 30% more than their ideal body weight. Cats were then randomly assigned to 1 of 4 weight-reduction diets (6 cats/diet) and were fed 25% of maintenance energy requirements per day. Diets consisted of CG-CO, CA-CO, CG-OB, and CA-OB, respectively, and were fed until cats lost weight and returned to their original lean body mass. Liver biopsy specimens and samples of perirenal, subcutaneous, and abdominal fat were obtained and analyzed for fatty acid content. RESULTS: Following weight loss, fatty acid composition of the liver and adipose tissue was primarily affected by protein quality in that cats fed CA had significantly higher percentages of 20:4(n-6) and 22:6(n-3) fatty acids than those fed CG. Cats fed the CG-CO diet had the lowest concentrations of LCPUFAs, suggesting that dietary lipids and protein quality each influence fatty acid composition in tissues. CONCLUSIONS AND CLINICAL RELEVANCE: These data provide direct evidence that dietary protein quality alters fatty acid composition of tissues during weight loss in cats. The fatty acid patterns observed suggest that protein quality may alter fatty acid composition through modulation of desaturase activity.     

The influence of omega-3 polyunsaturated fatty acids feeding on composition of fatty acids in fatty tissues and eggs of laying hens

The paper deals with supplementation of hen diet with oils with increased content of omega-3 polyunsaturated fatty acids (PUFA) and occurrence of fatty acids (FA) in fatty tissues and eggs of laying hens after the respective supplementation. The experiment was carried out on 30 laying hens of ISA BROWN hybrid, divided to three groups (A, B, C). For the period of three weeks the group A was administered flax-seed oil, group B served as a control and group C was fed base rations supplemented with fish oil. In addition to that the diet of groups A and C was supplemented with vitamin E as an antioxidant. Administration of the oils as a source of omega-3 PUFA increased their concentration in both the fatty tissues and egg-yolk which resulted in the change of the ratio of omega-6 and omega-3 PUFA. No influence of flax-seed and fish oil on concentration of alpha-tocopherol in egg-yolk was observed.     

Breed differences and heterosis in triacylglycerol fatty acid composition of bovine adipose tissue

Subcutaneous adipose tissues were biopsied in purebred Jersey (n=17), purebred Limousin (n=17) and reciprocal F₁ Jersey × Limousin crossbred (n=33) calves at the age of 9–10 months. Triacylglycerol fatty acids were extracted and analysed for sex and breed differences. Heterosis, additive and maternal variances were estimated. All calves were pasture‐fed in a single management group and biopsied from the same anatomical site. Heifer calves had significantly higher proportions of palmitoleate, total mono‐unsaturated fatty acids, desaturation index and lower stearate than steer calves. Significant breed differences were observed in that Limousin calves had the highest proportions of palmitate and total saturated fatty acids, whereas Jersey calves had the most palmitoleate and desaturation index. Dominance effects were evident in the proportions of palmitate, stearate, desaturation and elongation enzyme indices due to the observed highly significant heterosis effect. Myristate, palmitate and total saturated fatty acids were considered heritable due to the observed highly significant additive genetic effect.     

The effect of feeding level and physiological status on total flow and amino acid composition of endogenous protein at the distal ileum in swine.

An experiment was conducted to investigate the effects of BW, feed intake, and the physiological condition of the animal on the loss and amino acid composition of endogenous protein in swine. Ten growing barrows and five multiparous sows were equipped with a T-cannula in the distal ileum for digesta collection. A protein-free diet was fed to all animals. The barrows were given free access to the experimental diet. The sows also were allowed to consume the diet on an ad libitum basis, and digesta were collected during lactation and in the following gestation period. In addition, digesta from the gravid sows were collected after restricting the sows to 2 kg of feed per day. For each animal group, the endogenous losses of protein and amino acids were calculated in relation to DMI, and the amino acid composition of endogenous protein was calculated. The total endogenous gut protein loss at the distal ileum of growing pigs, lactating sows, and gestating sows, given free access to feed, was 12.4, 9.4, and 11.2 g/kg DMI, respectively. These values were not different (P > .10). However, when gestating sows were fed only 2 kg/d, 17.8 g of endogenous protein was lost per kilogram of DMI, which was higher (P < .05) than for any of the other groups. This difference was mainly caused by higher (P < .05) losses of glycine, proline, and serine. There were no differences (P > .05) in amino acid composition of endogenous protein between growing pigs, lactating sows, and gestating sows given free access to feed, but restricted-fed gestating sows had an amino acid composition of endogenous protein that was significantly different from that of the other groups. The results from the experiment showed that age, BW, and the physiological condition of the animal have little or no effect on the amount of endogenous protein and amino acids lost at the distal ileum of hogs if calculated in relation to DMI. Likewise, the amino acid composition was not affected by the BW or physiological condition of the animal. However, DMI had a significant effect on endogenous protein losses in sows as well as on amino acid composition of endogenous protein.     

Maternal obesity upregulates fatty acid and glucose transporters and increases expression of enzymes mediating fatty acid biosynthesis in fetal adipose tissue depots

Maternal nutrient restriction leads to alteration in fetal adipose tissue, and offspring from obese mothers have an increased risk of developing obesity. We hypothesized that maternal obesity increases fetal adipogenesis. Multiparous ewes (Columbia/Rambouillet cross 3 to 5 yr of age) carrying twins were assigned to a diet of 100% (Control; CON; n = 4) or 150% (Obese; OB, n = 7) of NRC maintenance requirements from 60 d before conception until necropsy on d 135 of gestation. Maternal and fetal plasma were collected and stored at -80°C for glucose and hormone analyses. Fetal measurements were made at necropsy, and perirenal, pericardial, and subcutaneous adipose tissues were collected from 7 male twin fetuses per group and snap frozen at -80°C. Protein and mRNA expression of fatty acid translocase [cluster of differentiation (CD) 36], fatty acid transport proteins (FATP) 1 and 4, insulin-sensitive glucose transporter (GLUT-4), fatty acid synthase (FASN), and acetyl-coA carboxylase (ACC) was evaluated. Fetal weight was similar, but fetal carcass weight (FCW) was reduced (P < 0.05) in OB versus CON fetuses. Pericardial and perirenal adipose tissue weights were increased (P < 0.05) as a percentage of FCW in OB versus CON fetuses, as was subcutaneous fat thickness (P < 0.001). Average adipocyte diameter was greater (P < 0.01) in the perirenal fat and the pericardial fat (P = 0.06) in OB fetuses compared with CON fetuses. Maternal plasma showed no difference (P > 0.05) in glucose or other hormones, fetal plasma glucose was similar (P = 0.42), and cortisol, IGF-1, and thyroxine were reduced (P ≤ 0.05) in OB fetuses compared with CON fetuses. Protein and mRNA expression of CD 36, FATP 1 and 4, and GLUT-4 were increased (P ≤ 0.05) in all fetal adipose depots in OB versus CON fetuses. The mRNA expression of FASN and ACC was increased (P < 0.05) in OB vs. CON fetuses in all 3 fetal adipose tissue depots. Fatty acid concentrations were increased (P = 0.01) in the perirenal depot of OB versus CON fetuses, and specific fatty acid concentrations were altered (P < 0.05) in subcutaneous and pericardial adipose tissue because of maternal obesity. In conclusion, maternal obesity was associated with increased fetal adiposity, increased fatty acid and glucose transporters, and increased expression of enzymes mediating fatty acid biosynthesis in adipose depots. These alterations, if maintained into the postnatal period, could predispose the offspring to later obesity and metabolic disease.