Heart fatty acid binding protein is upregulated during porcine adipocyte development

Heart fatty acid binding protein (H-FABP) has been associated with intramuscular fat content in pigs. In the current study, we showed that expression of H-FABP mRNA in adipose tissue of adult pigs was 8.5% of that in heart and 30% of that in skeletal muscle, and that H-FABP mRNA level was more than 10% of that of adipocyte fatty acid binding protein mRNA in adipose tissue. Levels of H-FABP mRNA reached a maximum in adipose tissue from 7-d neonates, with no further increase in the adult. Also, H-FABP mRNA was induced during adipogenic differentiation of stromal-vascular cells derived from adipose tissue and skeletal muscle. In conclusion, H-FABP may play a role in adipose tissue development and function in the pig.     

The effect of porcine somatotropin supplementation in pigs on the lipid profile of subcutaneous and intermuscular adipose tissue and longissimus muscle.

The effect of porcine somatotropin (pST) on the lipid profiles of adipose tissue and muscle was investigated. Sixteen crossbred barrows were injected daily with either 3 mg of pST or a placebo. After slaughter, total lipid and fatty acid composition of raw subcutaneous (SC) adipose and intermuscular (IM) adipose tissue and longissimus muscle were determined. The SC adipose tissue from pST-treated pigs had a 7.5% decrease in total lipid content; specific fatty acids 16:0, 18:0, and 18:1(n-9)c decreased most. The IM fat from pST-treated pigs had lower levels of 16:0 and 20:0. There was no effect of pST treatment on the lipid profile of the longissimus muscle. The data suggest that pST treatment produces small but significant changes in the saturated fatty acid content of adipose tissue in pigs.     

Regulation of hepatic peroxisome proliferator‐activated receptor α expression but not adiponectin by dietary protein in finishing pigs

Soy protein regulates adiponectin and peroxisome proliferator‐activated receptor α (PPARα) in some species, but the effect of dietary soy protein on adiponectin and PPARα in the pig has not been studied. Therefore, the objective of this study was to determine whether soya bean meal reduction or replacement influences serum adiponectin, adiponectin mRNA, serum metabolites and the expression of PPARα and other genes involved in lipid deposition. Thirty‐three pigs (11 pigs per treatment) were subjected to one of three dietary treatments: (i) reduced crude protein (CP) diet containing soya bean meal (RCP‐Soy), (ii) high CP diet containing soya bean meal (HCP‐Soy) or (iii) high CP diet with corn gluten meal replacing soya bean meal (HCP‐CGM) for 35 days. Dietary treatment had no effect on overall growth performance, feed intake or measures of body composition. There was no effect of dietary treatment on serum adiponectin or leptin. Dietary treatment did not affect the abundance of the mRNAs for adiponectin, PPARα, PPARγ2, lipoprotein lipase or fatty acid synthase in adipose tissue. The mRNA expression of PPARα, PPARγ2, lipoprotein lipase or fatty acid synthetase in loin muscle was not affected by dietary treatment. In liver tissue, the relative abundance of PPARα mRNA was greater (p < 0.05) in pigs fed the HCP‐Soy diets when compared to pigs fed RCP‐Soy or HCP‐CGM diets. Hepatic mRNA expression of acyl‐CoA oxidase or fatty acid synthase was not affected by dietary treatment. Western blot analysis indicated that hepatic PPARα protein levels were decreased (p < 0.05) in pigs fed the RCP‐Soy diets when compared to pigs fed the HCP‐Soy diets. These data suggest that increasing the soy protein content of swine diets increases hepatic expression of PPARα without associated changes in body composition.     

Fatty acid patterns of dog erythrocyte membranes after feeding of a fish-oil based DHA-rich supplement with a base diet low in n-3 fatty acids versus a diet containing added n-3 fatty acids

Background

In dogs, increasing the tissue n-3 fatty acid (FA) content is associated with potential benefit in some medical conditions, e.g. atopic dermatitis, cancer or heart disease. Therefore effectively and conveniently increasing tissue n-3 FA levels in dogs is of interest. Incorporation of dietary n-3 FA into cell membranes may be studied by FA analysis of erythrocyte membranes (EM), because of the correlation of its FA composition with the FA composition of other cells. Aim of the study was to determine whether an n-3 FA additive added to a control diet is as effective in increasing EM n-3 FA content as feeding an n-3 FA enriched diet. Furthermore the time course of the incorporation of dietary n-3 FA into canine EM was investigated.

Methods

Thirty dogs were randomly divided into three dietary groups with ten dogs per group. CONT got a dry dog food diet which did not contain EPA or DHA. FO got a dry dog food diet with a high EPA and DHA content. ADD got the CONT diet combined with an n-3 FA additive rich in DHA and EPA. After a feeding period of 12 weeks the additive was discontinued in ADD and these dogs were fed CONT diet for another four weeks to observe washout effects. Erythrocyte lipids were extracted from venous blood samples and their FA composition was determined by gas chromatography. The Mann-Whitney-U-test was used to detect significant differences between the different groups and time points.

Results

After one week the proportions of n-3 FA, DHA and EPA were already significantly increased in ADD and FO, apparently reaching a plateau within eight weeks. In our study DHA and not EPA was preferably incorporated into the EM. After discontinuing the administration of the additive in ADD, the n-3 FA values declined slowly without reaching baseline levels within four weeks.

Conclusions

In dogs, an increase of dietary n-3 FA content leads to a rapid inclusion of n-3 FA into EM, regardless of whether the n-3 FA are offered as an enriched diet or as a normal diet supplemented with an n-3 FA additive.     

Response of plasma fatty acid profiles to changes in dietary n‐3 fatty acids and its correlation with erythrocyte fatty acid profiles in dogs

An elevated level of long‐chain n‐3 fatty acids (FA) in tissue membranes has a positive influence on the progression and treatment of many diseases. Therefore, dietary supplementation of n‐3 FA is recommended in some diseases. Even though n‐3 FA are absorbed readily from the diet, their incorporation into tissues may be compromised in diseased animals. In a clinical setting, it is desirable to monitor the success of dietary intervention. Plasma FA as well as erythrocyte membrane (EM) FA can be used to monitor dietary FA intake. This study compares FA from EM and plasma with regard to their reaction time and reliability for monitoring dietary changes of tissue FA profiles in dogs. Thirty dogs were divided into three groups and fed for 12 weeks. The control group (CONT) was fed a commercial standard diet low in n‐3 FA. One group received the standard diet and 85 mg/kg body weight of a docosahexaenoic acid (DHA) concentrate (ADD). The third group was fed a commercial dog food containing fish oil (FO), which is rich in eicosapentaenoic acid (EPA). EM and plasma FA profiles were analysed by GC separately. Data on EM FA were published recently. n‐3 FA in plasma reached the new level after 2 weeks (8 weeks in EM). Dietary differences between DHA and EPA are obvious after 1 week already. The concomitant decrease in plasma n‐6 FA differed between ADD and FO. In general, the correlation of n‐6 FA between plasma and EM was low. We therefore conclude that analysis of plasma FA is sufficient for monitoring a diet‐induced increase in tissue n‐3 FA in dogs. However, EM FA should be analysed if the effect of dietary intervention on tissue n‐6 FA is important.     

Molecular cloning and tissue expression of chicken AdipoR1 and AdipoR2 complementary deoxyribonucleic acids

AdipoR1 and AdipoR2 belong to a novel class of transmembrane receptors that mediate the effects of adiponectin. We have cloned the chicken AdipoR1 and AdipoR2 complementary deoxyribonucleic acids (cDNA) and determined their expression in various tissues. We also investigated the effect of feed deprivation on the expression of AdipoR1 or AdipoR2 mRNA in the chicken diencephalon, liver, anterior pituitary gland, and adipose tissue. The chicken AdipoR1 and AdipoR2 cDNA sequences were 76-83% identical to the respective mammalian sequences. A hydrophobicity analysis of the deduced amino acid sequences of chicken AdipoR1/AdipoR2 revealed seven distinct hydrophobic regions representing seven transmembrane domains. By RT-PCR, we detected AdipoR1 and AdipoR2 mRNA in adipose tissue, liver, anterior pituitary gland, diencephalon, skeletal muscle, kidney, spleen, ovary, and blood. AdipoR1 or AdipoR2 mRNA expression in various tissues was quantified by real-time quantitative PCR, and AdipoR1 mRNA expression was the highest in skeletal muscle, adipose tissue and diencephalon, followed by kidney, ovary, liver, anterior pituitary gland, and spleen. AdipoR2 mRNA expression was the highest in adipose tissue followed by skeletal muscle, liver, ovary, diencephalon, anterior pituitary gland, kidney, and spleen. We also found that a 48 h feed deprivation significantly decreased AdipoR1 mRNA quantity in the chicken pituitary gland, while AdipoR2 mRNA quantity was significantly increased in adipose tissue (P<0.05). We conclude that the AdipoR1 and AdipoR2 genes are ubiquitously expressed in chicken tissues and that their expression is altered by feed deprivation in the anterior pituitary gland and adipose tissue.     

Influence of exogenous application of n-3 fatty acids on meat quality, lipid composition, and oxidative stability in pigs.

The effect of dietary n-3 fatty acids on the fatty acid composition and lipid peroxidation of different tissues in pigs were studied. 20 castrated male pigs were included in this investigation, one half was fed daily a diet containing 1.3 g n-3 fatty acids/kg diet (control) and 10 pigs were fed a diet containing 14 g n-3 fatty acids/kg diet (n-3 diet) at the growing-finishing period. The intake of dietary n-3 fatty acids increased the concentration of these fatty acids in backfat, and the neutral and polar fractions of skeletal muscle and heart homogenates. The polar fraction showed an increased relative concentration of n-3 fatty acids in comparison to control, while the n-6 fatty acid content was reduced. In heart homogenates there was an enlargement of n-3 fatty acids both in polar lipids and in neutral lipids whilst n-6 fatty acids were decreased. Feeding n-3 fatty acid enriched diet had no influence on meat quality parameters drip loss, meat colour or pH value. The lipid peroxidation (measured as malondialdehyde equivalents) was in the order liver > heart > skeletal muscle with higher values in the n-3 group. However, by stimulation of oxidation by Fe2+/ascorbate for 3 hours the order of oxidative products in the n-3 group was muscle > liver > heart, whereas in the control group the order was liver > heart = muscle. Summarized, feeding a highly n-3 fatty acid enriched diet caused an incorporation of these fatty acids and increased the susceptibility to peroxidation in all investigated tissues.     

Analysis of myostatin and its related factors in various porcine tissues

Myostatin is expressed in skeletal muscle tissue where it functions to suppress myoblast proliferation and myofiber hypertrophy. Recently, myostatin was detected in the tendon, mammary gland, and adipose tissue of mice. We sought to determine whether myostatin is expressed in the liver, spleen, lung, and kidney of pigs. Real-time PCR and Western blots demonstrated that myostatin, follistatin, decorin, and activin receptor IIB (ActRIIB) mRNA and proteins were expressed in skeletal muscle, heart muscle, and adipose tissue, and also in liver, spleen, lung, kidney, and cultured fibroblasts. The relative abundance of myostatin was closely related to follistatin and decorin in porcine tissues. Immunohistochemical analysis further demonstrated the presence of myostatin, follistatin, and decorin in the skeletal muscle, adipose tissue, heart muscle, liver, spleen, lung, and kidney of pigs. These results suggest that myostatin could be associated with certain functions of the internal organs, such as energy metabolism or fibrosis. We conclude that myostatin is a factor broadly expressed in the internal organs and muscle tissues of pigs.     

Growth, carcass characteristics, and lipid composition of adipose tissue and muscle of pigs fed canola

Sixty-one finishing pigs (53.4 kg) were fed a control diet (containing soybean meal) or diets containing 20% intact canola (IC) or 20% ground canola (GC) for 8 wk. Diets were not isocaloric. Daily gain and feed efficiency were not affected by dietary treatment, but pigs fed GC ate less than pigs fed either IC or the control diet. Carcass measurements, obtained on 43 of the pigs, were not affected by diet. For 27 pigs, fatty acid composition of perirenal adipose tissue (PRF), subcutaneous adipose tissue (SCF), and longissimus muscle (LDM) was analyzed. Nine pigs (three per treatment) were randomly selected for fatty acid composition analysis of intramuscular adipose tissue (IMF) and for cholesterol analysis of several tissues. Pigs fed canola had greater (P less than .05) proportions of mono- and polyunsaturated fatty acids and less (P less than .05) saturated fatty acids in PRF and SCF. The differences were more pronounced for PRF than for SCF. In the LDM, pigs fed canola tended to have elevated levels of unsaturated fatty acids at the expense of the saturated fatty acids, but this effect was significant for linolenic acid only. The fatty acid composition of IMF was not affected by diet (P greater than .05). Diet did not alter the cholesterol content of the tissues, but cholesterol in IMF was higher (P less than .05) than in PRF, SCF, and LDM. In conclusion, 20% IC or GC did not alter growth performance or carcass characteristics of pigs. Feeding of canola increased the degree of unsaturation of PRF and SCF, but it had less effect on IMF and LDM.     

猪FoxO1基因cDNA部分序列的克隆及其组织表达

根据人、黑猩猩及大鼠等物种FoxO1基因同源序列设计引物,利用RT-PCR方法从猪肝脏中克隆FoxO1基因cDNA的部分序列,组织特异性表达分析表明,FoxO1基因在1日龄和9月龄猪的肝、肺、肾、脾、心、胃、皮下脂肪、内脏脂肪、背最长肌和股四头肌等组织中均表达,只是表达丰度随发育阶段和组织的不同有所差异。1日龄猪的内脏脂肪中FoxO1的表达丰度最高,心脏和骨骼肌中相对较低;而9月龄猪的脾脏中FoxO1相对表达丰度最高,明显高于免疫机能尚未完全建立的初生猪,显示出FoxO1可能在机体的免疫调节中起一定作用,另外,9月龄猪的FoxO1表达丰度不仅在平滑肌和骨骼肌中有显著差异,而且在不同类型的骨骼肌中也存在显著差异,显示出FoxO1的表达可能与骨骼肌类型和运动强度有关。     

Effects of soyabean meal‐ or whey‐based diets on lipid metabolism in weaned piglets

The present study aimed to test the hypothesis that dietary protein source influences lipid metabolism‐related parameters weaned piglets. The effects of soyabean meal (SB) and whey proteins (WP) on gene expression of several genes involved in the lipogenic process in liver, visceral (VAT) and subcutaneous (SAT) adipose tissues, plasma insulin concentration and fatty acid (FA) profile were investigated in 18 weaned piglets. Weaned piglets were fed one of two diets containing either SB or WP as the main protein source. Following a 10‐h fasting period, plasma insulin concentration and FA profile were assessed at 56 and 72 days of age, whereas gene expression in liver, VAT and SAT was assessed at 72 days of age. Plasma insulin concentration was not affected by diet, although it was 40% lower in SB fed pigs. The SB pigs had lower 14:0 (p < 0.01) and higher 18:3n‐3 (p < 0.001) levels in plasma in comparison with WP pigs. However, these changes were attributed to background differences in the dietary FA profile and not to a direct protein source effect. Gene expression of sterol regulatory element‐binding protein 1 (SREBP‐1) in liver and VAT were lower (p < 0.01 and p < 0.05, respectively) in SB compared to WP fed piglets, but no differences occurred in SAT. No changes were observed in sterol regulatory element‐binding protein 2, liver X receptor, peroxisome proliferator‐activated receptors α and γ and plasminogen activator inhibitor 1 mRNA levels, either in liver or in adipose tissues. In conclusion, dietary protein source, accompanied likely by side alterations in the dietary composition, affects lipid metabolism in pigs through the downregulation of SREBP‐1, which is a crucial determinant of lipogenic process.     

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.     

Enzymes of glucose and fatty acid metabolism of liver, kidney, skeletal muscle, adipose tissue and mammary gland of lactating and non-lactating sheep

The effect of peak lactation on the activities of a number of enzymes of glucose and lipid metabolism of perirenal and subcutaneous adipose tissue, skeletal muscle, liver, kidney cortex and mammary parenchyma of sheep are described. Enzymes studied included hexokinase (glucose utilization), pyruvate carboxylase (gluconeogenesis), pyruvate dehydrogenase (glucose oxidation and production of acetyl CoA for fatty acid synthesis), acetyl CoA carboxylase (fatty acid synthesis) and glycerol-3-phosphate acyltransferase (fatty acid esterification). Major changes that were found include a decrease in activities of enzymes of fatty acid synthesis and esterification in adipose tissues, decreased activity of pyruvate dehydrogenase in muscle and adipose tissues and increased pyruvate carboxylase; there was no change in activities of enzyme of fatty acid esterification in liver. Activities of hexokinase, acetyl CoA carboxylase and glycerol-3-phosphate acyltransferase have been estimated per tissue; this shows the quantitative importance of limiting glucose utilization by muscle and of suppression of fatty acid synthesis in adipose tissue for efficient partitioning of nutrients for milk production.     

STC-1基因在大、小体型猪中表达与分布的差异分析

试验分别采集40日龄小体型猪（巴马猪）和大体型猪（大白猪）的心脏、肝脏、脾脏、肺脏、肾脏、头骨、骨骼肌组织,利用实时荧光定量PCR检测斯钙素-1（stanniocalcin 1,STC-1）基因mRNA在各个组织中的表达水平,并通过Western blotting检测STC-1蛋白在各个组织中的分布。实时荧光定量PCR检测结果表明,STC-1基因mRNA在巴马猪和大白猪肺脏、肾脏中相对表达水平较高,在骨骼肌中的表达水平最低;除心脏和骨骼肌外,巴马猪其余各组织中STC-1基因mRNA表达水平均显著高于大白猪（P < 0.05）。Western blotting检测结果表明,巴马猪肝脏中STC-1蛋白的表达量最高,而大白猪脾脏中STC-1蛋白表达量最高,两者差异显著（P < 0.05）;巴马猪肺脏、肝脏、骨骼肌及心脏组织中STC-1蛋白表达量均极显著高于大白猪（P < 0.01）;而巴马猪肾脏、脾脏中STC-1蛋白表达量极显著低于大白猪（P < 0.01）。本研究首次对大、小体型猪不同组织的STC-1基因mRNA表达水平及其STC-1蛋白分布进行检测,导致该基因表达与分布差异的原因可能与两种猪受外界环境应激及生长发育差异有关。     

Expression and Distribution Difference Analysis of STC-1 Gene in Big and Small Body Shape Pigs

The heart,liver,spleen,lung,kidney,skull,skeletal muscle were collected from 40-day-old Bama Mini pig and Large White pig,stanniocalcin 1(STC-1) gene mRNA and STC-1 protein were detected with Real-time PCR and Western blotting methods, respectively. The Real-time PCR results showed that the expression level of STC-1 gene mRNA was higher in lung and kidney, but was the lowest in skeletal muscle of Bama Mini pig and Large White pig. Except for heart and skeletal muscle tissues, the expression level of STC-1 gene mRNA in other tissues of Bama Mini pig was significantly higher than Large White pig (P < 0.05).The Western blotting results showed that the STC-1 protein distribution were the highest in liver and spleen of Bama Mini pig and Large White pig, respectively, and the difference was significant (P < 0.05). The STC-1 protein expression in lung, liver, skeletal muscle and heart of Bama Mini pig were extremely significantly higher than Large White pig (P < 0.01),and the STC-1 protein expression in kidney and spleen of Bama Mini pig were extremely significantly lower than Large White pig (P < 0.01). STC-1 gene mRNA and protein were firstly detected in different tissues from big and small body shape pigs,this might have a relationship with various external environments stress and development.     

Quantitative analysis of beta-adrenergic receptor subtypes in pig tissues

The density and distribution of beta1- and beta2-adrenergic receptors (betaAR) in porcine adipocytes, skeletal muscle, heart, lung, and liver were investigated using competitive displacement of ligand binding with subtype-selective ligands. Three experimental approaches were used to estimate the distribution of betaAR subtypes in adipocytes. Two approaches involved simultaneous linear regression analysis of multiple competitive displacement curves with the beta1AR-selective antagonist CGP 20712A and the beta2AR-selective ligand BRL 37344. For the third approach, radioligand saturation assays were perfomed using a concentration of CGP 20712A that completely blocked the beta1AR. All three approaches indicated the presence of multiple betaAR subtypes in porcine adipocytes and gave similar estimates for the proportion of these subtypes. Saturation assays in the presence of the beta1AR blocker CGP 20712A were conducted to determine the distribution of the betaAR subtypes in skeletal muscle, heart, lung, and liver. The proportions of the beta1AR and beta2AR were 81:19, 59:41, 72:28, 58:42, and 50:50 for adipose, skeletal muscle, heart, lung, and liver, respectively. These estimates based on receptor protein were consistent with published estimates of mRNA abundance in pig tissues but differ from estimates for other species. The predominance of beta1AR in adipocytes and skeletal muscle may contribute to the reduced efficacy of select betaAR agonists in pigs compared to other species because most of the ligands evaluated in growth studies are purported to be beta2AR selective. The density of the betaAR varied among tissues in the following order: heart = lung > adipocytes > skeletal muscle or = liver.