Dietary pea protein stimulates bile acid excretion and lowers hepatic cholesterol concentration in rats

It has been shown that some dietary plant proteins beneficially influence lipid metabolism in animals. The effect of pea protein in this respect however has not yet been investigated. Therefore, we studied the effect of purified pea protein on the lipid metabolism in rats. Twenty-four rats received diets with either 200 g/kg of casein or purified pea protein for 16 days. Concentrations of triacylglycerols in liver, plasma and lipoproteins did not differ between both groups of rats. However, rats fed the pea protein diet had a lower concentration of total cholesterol in the liver and the very low density lipoproteins (VLDL) fraction than rats fed the casein diet (p < 0.05); cholesterol concentration in plasma, low density lipoproteins (LDL) and high density lipoproteins (HDL) did not differ between both groups. Rats fed pea protein moreover had an increased mRNA concentration of cholesterol-7α-hydroxylase in the liver and an increased amount of bile acids excreted via faeces compared with rats fed casein (p < 0.05). Concomitantly, mRNA concentrations of sterol regulatory element-binding protein (SREBP)-2 and its target genes 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and LDL receptor in the liver were increased in rats fed pea protein (p < 0.05). The data of this study suggests that pea protein stimulates formation and excretion of bile acids, which leads to a reduced hepatic cholesterol concentration and a reduced secretion of cholesterol via VLDL. An increased gene expression of SREBP-2 and its target genes HMG-CoA reductase and LDL receptor may be a means to compensate for the increased loss of cholesterol for bile acid synthesis.     

Lipid concentrations of fillets, liver, plasma and lipoproteins of African catfish, Clarias gariepinus (Burchell 1822), fed diets with varying protein concentrations

This study investigated the effect of the dietary protein concentration on lipid concentrations in fillet and liver and concentrations of lipids in plasma and lipoproteins in African catfish. Two experiments were carried out, in which African catfish were fed diets with various protein concentrations. In experiment 1, semisynthetic diets with various concentrations of casein (350, 450 or 550 g protein/kg) were used. In experiment 2, diets were based on a commercial trout diet supplemented with various amounts of casein or carbohydrates, resulting in protein concentrations between 282 and 545 g/kg diet. In both experiments, the dietary protein concentration had a significant effect on growth, feed conversion ratio and carcass composition. Maximum of body weight gains and feed efficiency ratios were reached in both experiments at the highest dietary protein concentrations. Increasing the dietary protein concentration continuously increased masses of fillets and reduced masses of the liver and adipose tissue in the abdominal cavity. Fish fed the diets with the highest protein concentrations had the lowest concentration of total lipids, triglycerides and cholesterol in the fillets, the highest percentage of polyunsaturated fatty acids (PUFA) in total lipids of fillets and the lowest concentrations of saturated fatty acids (SFA). Fish fed the diets with the highest protein concentration also had the lowest concentrations of triglycerides in the liver, the highest percentages of PUFA in liver total lipids and the lowest percentages of SFA. Moreover, fish fed diets with high protein concentrations (501 and 545 g/kg) had significantly lower concentrations of triglycerides, cholesterol and phospholipids in plasma than fish fed diets with lower protein concentrations. In conclusion, this study shows that the dietary protein concentration does not only influence growth, feed efficiency and carcass composition in African catfish, but also influences their lipid metabolism and lipid concentrations of liver and fillet.     

Growth and adipose tissue metabolism in young pigs fed cimaterol with adequate or low dietary protein

The beta-adrenergic agonist, cimaterol, was fed to young growing pigs to determine whether the carcass compositional changes observed in finishing pigs fed a beta-adrenergic agonist would be manifest in young animals. Furthermore, because cimaterol increased the deposition of lean mass in finishing pigs, it could have a protein sparing effect in young pigs that are rapidly accreting muscle mass and have a high dietary protein requirement. Pigs were fed cimaterol (at 0, .25 and .50 mg X kg-1 diet) and either an adequate (18%) or restricted (14%) protein diet from about 10 to 60 kg body weight. Pigs that were fed the 14 compared with 18% protein diet grew slower and ate less but had the same gain-to-feed ratio. These pigs also had shorter carcasses, less lean muscle and more fat deposition (assessed by carcass measurements and carcass chemical composition) than pigs that received adequate protein. Plasma protein and albumin concentrations were greater and plasma cholesterol, triglyceride and fatty acid concentrations were lower in pigs fed high compared with low dietary protein. Dietary cimaterol had no effect on any of the growth or carcass variables or on adipose tissue metabolism. When fed the high protein diet, cimaterol-supplemented pigs had smaller livers and stomachs. Dietary cimaterol did not have any major detectable effects on these young pigs, nor was there any evidence for a protein sparing effect.     

Effects of combining three fungal phytases with a bacterial phytase on plasma phosphorus status of weanling pigs fed a corn-soy diet

The objective of this study was to determine possible synergistic effects of supplementing one of three fungal phytases: Aspergillus fumitagus PhyA (AFP),A. niger PhyA (ANP), or Peniophora lyci phytase (PLP) with an Escherichia coli AppA phytase (EP) in diets for pigs. Three experiments, each lasting for 4 wk, were conducted with a total of 106 weanling pigs (5 wk old). The corn-soybean meal basal diet (BD) contained no supplemental inorganic P. In Exp. 1, 35 pigs (8.6 +/- 1.0 kg BW) were fed (as-fed basis) BD + AFP at 750 U/ kg of feed, BD + inorganic P (0.2% P), or BD + PLP at 500, 750, or 1,000 U/kg feed. Pigs fed BD + AFP or BD + 0.2% P had higher (P < 0.05) plasma inorganic P concentrations than those fed BD + PLP at the end of the trial (wk 4). In Exp. 2, 35 pigs (8.1 +/- 0.9 kg BW) were fed BD + AFP, EP, PLP, a 1:1 mix of AFP:EP, or a 1:1 mix of PLP:EP at 500 U/kg. Pigs fed the AFP:EP mixture had growth performance and plasma measures similar to those fed either enzyme alone. Pigs fed the PLP:EP mixture had lower (P < 0.05) plasma alkaline phosphatase activity than those fed BD + PLP. Pigs fed BD + PLP had lower (P < 0.05) plasma inorganic P concentrations than pigs fed BD + EP, and higher (P < 0.05) plasma alkaline phosphatase activity than all other groups at wk 4. In Exp. 3, 36 pigs (9.1 +/- 1.2 kg BW) were fed BD + ANP, EP, or a 1:1 mix of ANP:EP at 500 U/kg feed. Pigs fed the two enzymes together had lower (P < 0.05) plasma inorganic P concentration than those fed BD + EP and lower (P < 0.05) plasma alkaline phosphatase activity than pigs fed BD + ANP at wk 4. In conclusion, although the four phytases showed different effects on plasma P status of weanling pigs, there was no synergistic effect between any of the three fungal phytases and the bacterial phytase on the plasma measures or growth performance under the conditions of the present study.     

Effects of protein deprivation on subsequent growth performance,gain of body components,and protein requirements in growing pigs

Forty-eight barrows were used in a 2 x 6 factorial arrangement to test a hypothesis that feeding a protein-deficient diet affects subsequent growth response by altering the efficiency of protein utilization. Barrows were individually fed either a 9% crude protein (CP) diet or an 18% CP diet from 20 to 30 kg of body weight (BW) (depletion phase). From 30 to 45 kg BW (realimentation phase), pigs were fed one of six experimental diets with CP levels of 11.8, 13.1, 14.3, 15.6, 18.8, and 21.8%. Four pigs were slaughtered at 20 kg BW to determine initial body composition. Four pigs from each treatment in depletion phase (a total of eight) were slaughtered at 30 kg BW, and all pigs from each treatment in realimentation phase (a total of 36) were slaughtered at 45 kg BW for subsequent compositional analysis. Pigs were bled at 20, 30, and 40 kg BW for blood urea nitrogen (BUN), insulin-like growth factor (IGF)-I, and IGF-binding protein (IGFBP) assays. Pigs were given three times the maintenance digestible energy requirement (3 x 120 kcal BW(-0.75) x d(-1)) in three equal meals daily. The feed allowance was adjusted every 3 d. During the depletion phase, pigs fed the 18% CP diet grew faster and more efficiently (P < 0.01) and gained more (P < 0.01) water and protein than did pigs fed the 9% CP diet. Pigs fed the 18% CP diet showed higher (P < 0.01) BUN values, IGF-I concentrations, and IGFBP ratios than pigs fed the 9% CP diet. During the realimentation phase, pigs fed the 9% CP diet during the depletion phase grew faster (P < 0.05), tended to grow more efficiently (P = 0.066), gained more water (P < 0.01), and tended to gain more protein (P = 0.068) than pigs fed the 18% CP diet during the depletion phase. Pigs fed the 9% CP diet during the depletion phase tended (P = 0.069) to have a higher protein requirement during the realimentation phase than pigs fed the 18% CP diet during the depletion phase. When measured at 40 kg BW, pigs fed the 9% CP diet had a lower (P < 0.05) BUN than pigs fed the 18% CP diet during the depletion phase. However, the plasma IGF-I concentration and IGFBP ratio at 40 kg BW were not affected by dietary CP level fed during the depletion phase. This study indicates that pigs fed a protein-deficient diet exhibit compensatory growth. During the period of compensatory growth, the requirement of CP for those pigs is higher than that of pigs previously fed an adequate diet. This study also suggests BUN can be used as an indicator of protein utilization efficiency and compensatory growth.     

Plasma hormones, metabolites, milk production, and cholesterol levels in Murrah buffaloes fed with Asparagus racemosus in transition and postpartum period

Ten dry and pregnant Murrah buffaloes were selected to investigate the effect of Asparagus racemosus feeding on hormones, metabolites, milk yield, and plasma cholesterol levels. The treatment groups of buffaloes were fed with A. racemosus (shatavari) @?150?g/day/animal during prepartum and @?300?g/day/animal during the postpartum period. Blood samples collected on ?6, ?4, ?2-week, day of parturition (0), and +2, +4, and +6-week postpartum were analyzed for plasma total cholesterol, triglycerides, HDL, low-density lipoproteins (LDL), prolactin, cortisol, and blood metabolites. Milk samples collected at weekly intervals (+1, +3, +5, and 7?weeks) were analyzed for total milk fat cholesterol. Prepartum plasma cholesterol concentrations were significantly higher in treatment group over the control (P?<?0.05). Mean plasma triglycerides, LDL cholesterol, HDL cholesterol, glucose, and nonesterified fatty acid (NEFA) levels varied nonsignificantly between groups. Plasma prolactin and cortisol concentrations were significantly (P?<?0.01) more in treatment group than in control group. On day of parturition, plasma prolactin, cortisol, LDL, and plasma total cholesterol were higher (P?<?0.01) in treatment group buffaloes in comparison to control group. A. racemosus feeding significantly (P?<?0.01) increased plasma prolactin, cortisol (P?<?0.01), and milk fat cholesterol (P?<?0.05) without affecting total cholesterol, HDL, LDL, glucose, and NEFA concentrations. The buffaloes of treatment group produced more milk (?@?0.526?kg/animal/day) suggesting thereby that A. racemosus is galactopoietic. It was concluded that feeding of A. racemosus increases plasma prolactin and cortisol and decreased plasma total cholesterol and LDL concentration.     

Progesterone production by cultured luteal cells in the presence of bovine low- and high-density lipoproteins purified by heparin affinity chromatography.

The objectives of this study were to separate plasma lipoprotein particles based on the presence (low-density lipoproteins; LDL) or absence of apolipoprotein B (high-density lipoproteins; HDL) and to compare the abilities of bovine LDL and HDL to stimulate progesterone production by bovine luteal cells in culture. Plasma lipoproteins were isolated by ultracentrifugation and separated into LDL and HDL by heparin affinity chromatography. Luteal cultures were treated with LDL or HDL cholesterol for 48 h on d 3 of the culture (d 0 = day of dissociation). Progesterone production by luteal cells increased in a dose-dependent manner with increasing concentrations of either LDL or HDL cholesterol. There were no differences in the ability of LDL or HDL cholesterol to stimulate luteal cells to produce progesterone. Because LDL and HDL were equally potent, and experiment was designed to investigate the ability of modified LDL or reconstituted particles without apolipoproteins to stimulate progesterone production. Stimulation of luteal cell progesterone production by lysine-modified LDL was 70% of unmodified LDL. Progesterone production in the presence of phosphatidylcholine liposomes or BSA containing cholesterol was 50 and 108% of that obtained with HDL or LDL. Evidence indicated that apolipoprotein-free particles that contained free cholesterol but not cholesterol esters stimulated luteal cells to produce progesterone.     

Effect of dietary nutrients on osteochondrosis lesions and cartilage properties in pigs

OBJECTIVE: To evaluate dietary ingredients involved in cartilage and bone metabolism and their influence on osteochondrosis lesions in swine. ANIMALS: 80 crossbred gilts (mean initial weight, 39 kg). PROCEDURES: Pigs (10 pigs/treatment) were fed a corn-soybean meal basal (control) diet or the basal diet supplemented with additional minerals (copper and manganese or silicon), amino acids (proline and glycine; a combination of leucine, isoleucine, and valine; or methionine and threonine), or fatty acids (provided by fish oil) for 84 days. Pigs were then slaughtered and the distal portion of the left femur was collected for determination of osteochondrosis lesions at the femoral condyle. After evaluation of external joint surfaces, the distal portion of the femur was sectioned to evaluate lesions in the growth plate and articular cartilage. Additionally, a cartilage specimen was obtained from the patella for analysis. RESULTS: Pigs fed diets containing high amounts of methionine and threonine or the diet containing all additional ingredients had significantly lower total severity scores, compared with scores for pigs fed the control diet or a diet supplemented with fish oil. Pigs fed diets containing additional proline and glycine, copper and manganese, methionine and threonine, or all additional ingredients had significantly lower overall scores, compared with scores for pigs fed the control diet or a diet supplemented with fish oil. CONCLUSIONS AND CLINICAL RELEVANCE: Dietary manipulation decreased the severity of osteochondrosis lesions, compared with results for pigs fed a control diet. However, additional research on optimal concentrations and combinations of dietary components is needed.     

The effects of thermal environment and spray-dried plasma on the acute-phase response of pigs challenged with lipopolysaccharide

Forty barrows (TR4 x C22) were weaned at 17 d of age (BW = 6.27 +/- 0.30 kg), housed (two pigs/pen) in a thermal-neutral environment (TN; constant 26.7 degrees C), and fed diets with or without 7% (as-fed basis) spray-dried plasma (SDP). On d 7, one pig/ pen was moved into a cold environment (CE; constant 15.6 degrees C). Pigs were fitted with jugular catheters on d 11. On d 12, 16 pigs per environment (eight pigs per dietary treatment) were challenged i.v. with 75 microg of lipopolysaccharide (LPS)/kg of BW. Blood samples were collected over a 4.5-h period. Pigs were then killed and tissue samples were harvested for messenger RNA (mRNA) analysis. From d 0 to 7, pigs fed SDP diets had a lower gain:feed ratio (G/F) than pigs fed no SDP (533 +/- 14 vs. 585 +/- 17 g/kg; P < 0.03). Pigs housed in the CE consumed more feed and had a lower G/F than pigs housed in TN from d 7 to 11 (P < 0.001). There were no environment x diet interactions from d 7 to 11 (P > 0.78). Baseline concentrations of serum ACTH and cortisol were lower in the TN pigs than in the CE pigs (P < 0.001). Pigs fed diets without SDP had lower serum cortisol concentrations over the 4.5-h period than pigs fed SDP (time x diet, P < 0.001). Serum concentrations of tumor necrosis factor-alpha (TNF-alpha) were highest for pigs consuming SDP in the CE, whereas there were no differences among the other treatments (time x diet x environment, P < 0.02). Pigs housed in the CE had higher serum interleukin-1beta (IL-1beta) (P < 0.001) and interleukin-6 (IL-6; P < 0.001) than TN pigs. Pigs fed SDP also had slightly higher serum IL-1beta concentrations (P < 0.10) and higher (P < 0.001) IL-6 concentrations than pigs fed no SDP. Pigs fed SDP had 9% lower liver and 13% lower thymus mRNA expression of tumor necrosis factor-alpha (TNF-alpha) than pigs that consumed no SDP (P < 0.06). Liver IL-1beta, IL-6, and LPS-binding protein mRNA were higher in the CE than in the TN (P < 0.03, P < 0.001, and P < 0.05; respectively). In addition, spleen TNF-alpha (P < 0.03) and IL-6 (P < 0.01) mRNA levels were higher in the CE than in the TN. Pigs consuming SDP and challenged with LPS responded with elevated serum concentrations of cortisol and cytokines compared with pigs fed diets with no SDP. Housing pigs in a CE increased the baseline concentrations of ACTH and cortisol, and when coupled with an LPS challenge, resulted in elevated serum and tissue mRNA levels of cytokines. Cold stress and feeding SDP during a LPS challenge may result in increased stress and immune responses in young pigs.     

The isolation, characterisation and quantification of the equine plasma lipoproteins

Plasma lipoproteins were isolated from eight Thoroughbred horses and eight Shetland ponies on the basis of particle size by gel filtration chromatography and according to density using rate-zonal ultracentrifugation. Three major classes corresponding to very low density lipoproteins (VLDL), low density lipoproteins (LDL) and high density lipoproteins (HDL) were identified and characterised by their lipid and apolipoprotein compositions. The particle size distributions of each class were determined by electron microscopy and non-denaturing polyacrylamide gradient gel electrophoresis. HDL was found to dominate the equine lipoprotein spectrum, accounting for 61 per cent of the total plasma lipoprotein mass (VLDL 24 per cent, LDL 15 per cent). The VLDL class was isolated as a single population of particles that were triglyceride rich and cholesterol, phospholipid and protein poor. Equine LDL was characteristically cholesterol rich and was found to be polydisperse comprising three subfractions that were discrete with respect to particle size and lipid composition. The HDL class was composed of homogeneous particles that were typically protein rich. Apolipoprotein (apo) B was the major protein of VLDL and LDL, and presented two components on polyacrylamide gel electrophoresis with molecular weights in the region of human apoB-100 and a third in VLDL similar to that of apoB-48. ApoA-I was the predominant protein in equine HDL. Although there were no breed differences in the physical or chemical properties of each lipoprotein class, the Shetland ponies had higher plasma triglyceride and VLDL concentrations than their Thoroughbred counterparts.     

Comparison of low-glycoalkaloid potato protein and fish meal as protein sources for weaner piglets

A total of 32 weaner piglets (Landrace×Yorkshire) with an average initial body weight of 9.6±1.2 kg, and 29.8±2.7 days of age, were used in a 28-day growth assay to compare low-glycoalkaloid potato protein with fish meal as the main protein source. The piglets were housed pair-wise in pens and were fed semi-ad libitum. During feeding the piglets were separated allowing individual feeding within the pen. Four diets were tested with varying proportions of a high quality fish meal (F) and low-glycoalkaloid potato protein (P): diet A (10% F); diet B (5% F and 5% P); diet C (2.5% F and 7.5% P) and diet D (10% P). On average, in weeks 1–4, the piglets on diets C and D had higher feed intakes (17%; P<0.01) and daily weight gains (18%; P<0.05) than the piglets on diets A and B. There was no effect of diet (P>0.05) on feed conversion. It can be concluded from the present study that low-glycoalkaloid potato protein can completely replace high quality fish meal in diets for weaner pigs. The improved feed intake and daily gain with increasing inclusion suggests that low-glycoalkaloid potato protein may be superior to fish meal as a protein source for weaner pigs.     

Inflammation-associated responses in piglets induced with post-weaning colibacillosis are influenced by dietary protein level

Forty piglets (average body weight = 5.32 kg) were used to investigate the effect of dietary crude protein (CP) content on immunological responses following a challenge with enterotoxigenic Escherichia coli (ETEC) K88. Pigs, housed 4 per pen, were randomly allotted to 2 diets: 1) a high, 225 g/kg CP diet (HCP) or 2) a low, 176 g/kg CP diet (LCP) supplemented with crystalline amino acids. Pigs were orally challenged with 6 mL of an ETEC K88 suspension containing 10¹⁰ cfu/mL on d 8 after weaning. Blood samples were collected from 10 pigs (1 pig/pen) on d 7 (at weaning), −24 h, 8 h, 72 h and 7 d after the challenge for determination of plasma urea N (PUN) and serum concentrations of tumor necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β) and haptoglobin (Hp). Tumor necrosis factor alpha, IL-1β and Hp were measured as indicators of inflammatory responses. The concentrations of serum TNF-α at 8 h, 72 h and 7 d after challenge were similar to the level observed at 24 h before challenge but higher (P < 0.05) than the weaning level. Pigs fed the LCP diet had lower (P = 0.032) concentrations of IL-1β (72 vs. 116 pg/mL) at 8 h post-challenge compared with those fed the HCP diet. Likewise, pigs fed the LCP diet tended to have lower (P = 0.088) concentration of Hp (9 vs. 25 mg/dL) compared with those fed the HCP diet at 8 h post-challenge. Compared with the weaning concentration, PUN concentration at 72 h after ETEC challenge was higher (P < 0.05) in pigs fed the HCP diet. The results indicate that the LCP diet supplemented with crystalline amino acids reduced inflammatory responses, as indicated by serum IL-1β, in piglets infected with ETEC K88.     

Growth performance, diet apparent digestibility, and plasma metabolite concentrations of barrows fed corn-soybean meal diets or low-protein, amino acid-supplemented diets at different feeding level

Two experiments, each with 36 barrows with high-lean-gain potential, were conducted to evaluate apparent nutrient digestibilities and performance and plasma metabolites of pigs fed corn-soybean meal diets (CONTROL) and low-protein diets. The low-protein diets were supplemented with crystalline lysine, threonine, tryptophan, and methionine either on an ideal protein basis (IDEAL) or in a pattern similar to that of the control diet (AACON). Amino acids were added on a true ileally digestible basis. The initial and final BW were, respectively, 31.5 and 82.3 kg in Exp. 1 and 32.7 and 57.1 kg in Exp. 2. In Exp. 1, the CONTROL and IDEAL diets were offered on an ad libitum basis or by feeding 90 or 80% of ad libitum intake. Pigs were fed for 55 d. In Exp. 2, the CONTROL, IDEAL, and AACON diets were offered on an ad libitum basis or by feeding 80% of the ad libitum intake. Pigs were fed for 27 d. Pigs fed the CONTROL diet had greater (P < 0.05) ADG and feed efficiency (G/F) than pigs fed the IDEAL (Exp. 1 and 2) and AACON diets (Exp. 2). As the level of feed intake decreased, ADG decreased (P < 0.05), but G/F tended to improve (P < 0.10) for pigs fed 90% of ad libitum in Exp. 1 and for pigs fed 80% of ad libitum in Exp. 2. In Exp. 1, the apparent total tract digestibilities of DM and energy were greater (P < 0.01) for pigs fed the IDEAL diet than for pigs fed the CONTROL diet. In Exp. 2, the apparent total tract digestibility of protein was greatest in pigs fed the CONTROL diet (P < 0.05) and was greater (P < 0.05) in pigs fed the AACON diet than in pigs fed the IDEAL diet. Plasma urea concentrations were lower in pigs fed the IDEAL diet than in pigs fed the CONTROL diet, regardless of feeding level. For pigs fed the CONTROL diet, plasma urea concentrations were lower when feed intake was 80% of ad libitum (diet level, P < 0.01). In summary, pigs fed the IDEAL and the AACON diets gained less and had lower plasma urea concentrations than pigs fed the CONTROL diet. Based on these data, it seems that the growth potential of pigs fed the IDEAL and AACON diets may have been limited by a deficiency of lysine, threonine, and(or) tryptophan and that the amino acid pattern(s) used was not ideal for these pigs.     

乳源性生物活性肽对新生IUGR仔猪肝脏抗氧化功能的影响

本试验选择苏太初生IUGR仔猪10窝共20头,配对分为4组:胰岛素组(I组)、牛乳组(M组)、酪蛋白酶解产物组(CH组)和酪蛋白组(C组),饲喂3d后宰杀。另选5只初生IUGR仔猪立即宰杀,作为0d对照组(A组)。M组喂牛乳,I组在牛乳中添加2.5mg/L胰岛素;C组用1.5%酪蛋白水溶液取代10%(V/V)的牛乳,CH组用1.5%酪蛋白酶解液取代10%(V/V)的牛乳。宰杀后分析肝脏和血浆中SOD活性和MDA含量以及血浆中GPT和GOT水平。试验结果显示:酪蛋白酶解物可显著降低肝脏和血浆MDA含量,提高SOD活性(P<0.05),胰岛素可显著降低血浆中MDA含量(P<0.05);3日龄仔猪GPT和GOT均高于初生仔猪,其中I组、C组和CH组GPT均显著高于M组(P<0.05)。结果提示:胰岛素和酪蛋白酶解物可提高IUGR仔猪肝脏的抗氧化功能,促进肝细胞的生长发育。     

The effects of birth weight and estimated breeding value for protein deposition on nitrogen efficiency in growing pigs

The effects of birth weight (BiW; low BiW [LBW] vs. high BiW [HBW]) and estimated breeding value (EBV) for protein deposition (low EBV [LBV] vs. high EBV [HBV]) on N retention, N efficiency, and concentrations of metabolites in plasma and urine related to N efficiency in growing pigs were studied. At an age of 14 wk, 10 LBW–LBV (BiW: 1.07 ± 0.09 [SD] kg; EBV: −2.52 ± 3.97 g/d, compared with an average crossbred pig with a protein deposition of 165 g/d), 10 LBW–HBV (BiW: 1.02 ± 0.13 kg; EBV: 10.47 ± 4.26 g/d), 10 HBW–LBV (BiW: 1.80 ± 0.13 kg; EBV: −2.15 ± 2.28 g/d), and 10 HBW–HBV (BiW: 1.80 ± 0.15 kg; EBV: 11.18 ± 3.68 g/d) male growing pigs were allotted to the experiment. The pigs were individually housed in metabolism cages and were subjected to an N balance study in two sequential periods of 5 d, after an 11-d dietary adaptation period. Pigs were assigned to a protein adequate (A) or protein restricted (R, 70% of A) regime in a change-over design. Pigs were fed 2.8 times the energy requirements for maintenance. Nontargeted metabolomics analyses were performed in urine and blood plasma samples. The N retention (in g/d) was higher in the HBW than in the LBW pigs (P < 0.001). The N retention (in g/[kg metabolic body weight (BW^0.75) · d]) and N efficiency, however, were not affected by the BiW of the pigs. The N retention (P = 0.04) and N efficiency (P = 0.04) were higher in HBV than in LVB pigs on the A regime but were not affected by EBV in pigs on the R regime. Restricting the dietary protein supply with 30% decreased the N retention (P < 0.001) but increased the N efficiency (P = 0.003). Nontargeted metabolomics showed that a hexose, free amino acids (AA), and lysophosphatidylcholines were the most important metabolites in plasma for the discrimination between HBV and LBV pigs, whereas metabolites of microbial origin contributed to the discrimination between HBV and LBV pigs in urine. This study shows that BiW does not affect N efficiency in the later life of pigs. Nitrogen efficiency and N retention were higher in HBV than in LBV pigs on the A regime but similar in HBV and LBV pigs on the R regime. In precision feeding concepts aiming to further optimize protein and AA efficiency in pigs, the variation in EBV for protein deposition of pigs should be considered as a factor determining N retention, growth performance, and N efficiency.     

Effect of dietary fish oil on the expression of genes involved in lipid metabolism in liver and skeletal muscle of lactating sows

This study investigated the hypothesis that dietary supplementation of fish oil as a source of n‐3 polyunsaturated fatty acids (PUFA) influences the expression of target genes of sterol regulatory element‐binding proteins (SREBP)‐1 and (SREBP)‐2 involved in triacylglycerol (TAG) synthesis and fatty acid and cholesterol metabolism in the liver, and moreover activates the expression of target genes of peroxisome proliferation‐activated receptor (PPAR)‐α involved in TAG and fatty acid catabolism in liver and skeletal muscle. Twenty lactating sows were fed a control diet or a fish oil diet with either 50 g of a mixture of palm oil and soya bean oil (4:1, w/w) or fish oil per kg. The diet of the fish oil group contained 19.1 g of n‐3 PUFA (mainly 20:5 n‐3 and 22:6 n‐3) per 100 g of total fatty acids, while the diet of the control group contained 2.4 g of n‐3 PUFA (mainly 18:3 n‐3) per 100 g of total fatty acids. The fish oil group had reduced relative mRNA concentrations of various target genes of SREBP‐1 involved in fatty acid and TAG synthesis in comparison with the control group (p < 0.05). Relative mRNA concentrations of target genes of PPARα involved in fatty acid catabolism in both liver and muscle, and mRNA concentrations of target genes of SREBP‐2 involved in cholesterol synthesis and uptake were not influenced by fish oil supplementation. Concentrations of cholesterol and TAG in plasma, fat content of milk and weight gains of litters during the suckling period were not different between the two groups of sows. In conclusion, this study suggests that fish oil has only minor effects on hepatic lipid metabolism, which are non‐critical with respect to milk production in sows.     

Effect of dietary conjugated linoleic acids on the distribution of fatty acids in serum lipoprotein fractions and different tissues of growing pigs

The effect of conjugated linoleic acid (CLA) on blood lipids [total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL) and triacylglycerols (TAG)] and the fatty acid distribution of the lipoprotein fractions, backfat, muscle fat, and liver lipids were examined in an experiment with two groups of 40 pigs [Pietrain x (Landrace x Large White)] each. The 20 female and 20 male castrated pigs of each group were fed with isoenergetic and isonitrogenous diets supplemented with either 20 g/kg rapeseed oil (control) or 20 g/kg CLA-TAG. The CLA preparation contained 54.2% pure CLA consisting of approximately two-thirds cis,trans/trans,cis-isomers and one-third trans,trans-isomers. The fatty acids of lipoproteins, backfat, muscle lipids and liver lipids were analysed by gas chromatograph (GC). CLA supplementation did not significantly influence blood lipids and the LDL to HDL ratio. In the CLA-fed pigs the very low-density lipoprotein (VLDL) contained higher saturated fatty acid (SFA) concentrations at the cost of the monounsaturated fatty acids (MUFA). The percentage of polyunsaturated fatty acids (PUFA) remained unchanged. The highest CLA content was analysed in VLDL (4.00%) followed by LDL (2.78%) and HDL (1.45%). The ratio of cis,cis to trans,trans isomers increased from VLDL over LDL to HDL. The content of SFA, probably in backfat and muscle lipids, increased whereas the part of MUFA decreased as a result of reduced Delta9-desaturase activity. The percentage of PUFA (without CLA) was higher in backfat of the control group in accordance with the dietary PUFA supply. This shift in the fatty acid distribution was not observed in the liver lipids. In all the three tissues analysed, the CLA-fed pigs had a significantly increased CLA content: the highest increase was in the backfat (5.65%), followed by liver lipids (2.41%), and muscle lipids (1.47%). An isomer-specific accumulation was observed for cis,cis-CLA isomers in muscle, and for trans,trans-CLA isomers in backfat. We conclude that CLA supplementation results in a higher SFA content in backfat and muscle lipids but not in liver lipids. There is a discrimination of the trans-10, cis-12 isomer and the trans,trans isomers in the formation of the cell membranes.     

Effect of dietary fish oil on fatty acid deposition and expression of cholesterol homeostasis controlling genes in the liver and plasma lipid profile: comparison of two animal models

The objective of the present study was to compare hepatic fatty acid deposition, plasma lipid level and expression of cholesterol homeostasis controlling genes in the liver of rats (Wistar Albino; n = 32) and pigs (Large White × Landrace; n = 32) randomly assigned into two groups of 16 animals each and fed 10 weeks the diet with either 2.5% of fish oil (F; source of eicosapentaenoic and docosahexaenoic acid, EPA+DHA) or 2.5% of palm oil (P; high content of saturated fatty acids; control). F‐rats deposited in the liver three times less EPA, but 1.3 times more DHA than F‐pigs (p < 0.05). Dietary fish oil relative to palm oil increased PPARα and SREBP‐2 gene expression much strongly (p < 0.01) in the pig liver in comparison with the rat liver, but expression of Insig‐1 and Hmgcr genes in the liver of the F‐pigs relative to the expression of these genes in the liver of the P‐pigs was substantially lower (p < 0.01 and p < 0.05 respectively) as compared to rats. When plasma lipid concentration in the F‐animals was expressed as a ratio of the plasma concentration in the P‐counterparts, dietary fish oil decreased HDL cholesterol less (p < 0.01), but LDL cholesterol and triacylglycerols more (p < 0.05 and p < 0.001 respectively) in rats than in pigs: more favourable effect of fish oil on rat plasma lipids in comparison with pigs can therefore be concluded. Concentration of total cholesterol and both its fractions in the rat plasma was negatively correlated (p < 0.01) with hepatic DHA, but also with unsaturated myristic and palmitic acid respectively. It has been concluded that regarding the similarity of the plasma lipid levels to humans, porcine model can be considered superior; however, using this model, dietary fish oil at the tested amount (2.5%) was not able to improve plasma lipid markers in comparison with saturated palm oil.     

Effect of chromium picolinate and chromium propionate on glucose and insulin kinetics of growing barrows and on growth and carcass traits of growing-finishing barrows

Two experiments were conducted to determine the effects of dietary Cr tripicolinate (CrPic) or Cr propionate (CrProp) on growth, carcass traits, plasma metabolites, glucose tolerance, and insulin sensitivity in pigs. In Exp. 1, 36 barrows (12 per treatment; initial and final BW were 20 and 38 kg) were allotted to the following treatments: 1) corn-soybean meal basal diet (control), 2) as 1 + 200 ppb Cr as CrPic, or 3) as 1 + 200 ppb Cr as CrProp. Growth performance data were collected for 28 d, and then 23 pigs (seven, eight, and eight pigs for treatments 1, 2, and 3, respectively) were fitted with jugular catheters and a glucose tolerance test (500 mg glucose/kg BW) and an insulin challenge test (0.1 IU of porcine insulin/kg BW) were conducted. Both CrPic and CrProp decreased (P < 0.05) ADG and ADFI but did not affect gain:feed (P > 0.10). Fasting plasma glucose, total cholesterol, urea N, insulin, and high-density lipoprotein cholesterol:total cholesterol concentrations were not affected (P > 0.10) by either Cr source. Pigs fed CrPic had lower (P < 0.02) fasting plasma NEFA concentrations than control pigs, but plasma NEFA concentrations of pigs fed CrProp were not affected (P > 0.10). During the glucose tolerance test, glucose and insulin kinetics were not affected by treatment (P > 0.10). During the insulin challenge test, glucose clearance was increased (P < 0.01) in pigs fed CrProp but not affected (P > 0.10) in pigs fed CrPic. Glucose half-life was decreased (P < 0.03) in pigs fed CrPic or CrProp, but insulin kinetics were not affected (P > 0.10). In Exp. 2, 48 barrows (four replicates of four pigs per replicate; initial and final BW were 23 and 115 kg) were allotted to the same dietary treatments in a growing-finishing study. Average daily gain, ADFI, and gain:feed were not affected (P > 0.10) by treatments. Carcass length tended (P = 0.10) to be greater in pigs fed CrPic than in pigs fed CrProp, but other carcass measurements were not affected (P > 0.10). Glucose kinetics from the insulin challenge test indicate that both CrPic and CrProp increase insulin sensitivity and that both Cr sources are bioavailable.     

Transiency of the different cholesterolaemic responses to dietary cellulose and psyllium in pigs and two strains of hamsters

The time course of the cholesterolaemic effects of dietary cellulose and psyllium was studied in two strains of hamsters and in pigs. In the first experiment, the ShHan:AURA strain from Harlan was used. Hamsters were first fed a cholesterol‐enriched (0.1%, w/w) semipurified diet containing 3% cellulose for a period of 2 weeks. Then, one group (n = 14) continued on the cellulose diet and another group (n = 14) was transferred to the psyllium diet. After 1.5 weeks on the diets, the psyllium‐fed hamsters showed a steep decrease in plasma cholesterol levels whereas the cellulose group maintained high cholesterol levels. Then, however, the cellulose‐fed hamsters showed a gradual decrease in plasma cholesterol levels and after 9.5 weeks on the diets, they had plasma cholesterol levels comparable to the hamsters fed psyllium. In the second study, the Lake View strain from Charles River was used. Two groups of hamsters (n = 14 per group) were fed a cholesterol‐enriched (0.1%, w/w) semipurified diet containing either 3% cellulose or 3% psyllium. The psyllium‐fed group had significantly lower plasma cholesterol concentrations than the cellulose group after 2, 4, and 6 weeks on the diets. After 8 weeks on the diets, however, the cholesterol levels in the cellulose group had decreased to levels similar to those in the psyllium group. In the third experiment, pigs were fed a cholesterol‐enriched (0.5%, w/w) semipurified diet containing either 5% cellulose or psyllium. After 1 and 2 weeks on the diets, the cellulose‐fed pigs had elevated plasma cholesterol concentrations, whereas the psyllium‐fed pigs maintained low cholesterol levels. After 3 weeks on the diets, the cholesterol concentrations in the cellulose‐fed pigs had decreased to the same level as in the psyllium‐fed pigs. There was no significant effect of cellulose and psyllium on liver cholesterol in the three studies, but psyllium tended to increase the faecal excretion of bile acids. Thus, the present studies showed a cholesterol lowering effect of dietary psyllium compared with cellulose in hamsters and pigs, but this effect was transient.