Influences of dietary protein sources and crude protein levels on intracellular free amino acid profile in the longissimus dorsi muscle of finishing gilts

Background： The current study was carried out to determine effects of dietary protein source and crude protein（CP）level on carcass characteristics, meat quality, and muscle amino acid（AA） profile in finishing gilts. The experiment was designed as a 2 × 2 factorial arrangement with two sources of dietary proteins（cottonseed meal, CSM vs. soybean meal, SBM） and two levels of CP（12 % vs. 14 %, as-fed basis）. Seventy-two crossbred gilts（89.5 ± 0.9 kg） were allotted to one of four dietary treatments in a randomized complete block design for a period of 28 d. All diets were formulated to be isoenergetic and similar concentrations of standardized ileal digestible essential AA covering the nutrient requirements of pigs.Results： Growth, carcass characteristics and meat quality were not affected by dietary protein source nor crude protein level（P ＆gt; 0.10） except that average daily feed intake was increased by CSM diets（P = 0.03）. Gilts offered reduced protein diets had lower muscle p H45min（P 〈 0.05）. Neither dietary protein source nor crude protein level influenced N deposition. However, reduced protein diets decreased N intake, N excretion, and serum urea nitrogen content, whilst improved N efficiency（P 〈 0.01）. CSM diets increased N intake（P = 0.04）,but did not depress N efficiency. The concentrations of phenylalanine, tryptophan, cysteine and tyrosine（P 〈 0.05） of the longissimus muscle were decreased when gilts offered CSM diets, while muscle intracellular free valine concentration was increased（P = 0.03）. The gilts offered reduced protein diets had greater intracellular concentrations of free methionine, lysine, and total AA in muscle（P 〈 0.05）.Conclusion： These results suggest that CSM could replace SBM as a primary protein source in finishing pig diets in terms of performance, N efficiency, carcass characteristics, and meat quality, but decrease the concentrations of muscle specific AA. Furthermore, the reduced protein diet played an important role in increasing muscle intracellular concentrations of specific free amino acids（FAA）, and in reducing the relative ratios of specific FAA to lysine in longissimus dorsi muscle of pig, whose biological meaning needs further studies.

Effect of Crossbreed on the Muscle Quality(Chemical Composition) in Yun-Ling Black Goats

Twenty castrated male goats, each of Yun-Ling Black goats （YLB goat）, N × YLB hybrid goats （Nubian ♂ ×Yun-Ling Black goats 9） and B × YLB hybrid goats （Boer ♂× Yun-Ling Black goats ♀）, were used to evaluate the effect of crossbreeding on the meat chemical composition in the YLB goats of China. After weaning of 90 days, all the experimental goats were reared on natural pasture when they were slaughtered at an age of 730 days. The longissimus dorsi （LD） and biceps femoris （BF） muscles were sampled from each carcass to determine chemical compositions. Both hybrid goats had higher protein content （P 〈 0.01） and lower fat content （P 〈 0.05） than the YLB goats in the two types of muscle. The inosinic acid contents of LD muscle for the YLB goats and the B × YLB hybrid goats were significantly higher （P 〈 0.05） than that for the N × YLB hybrid goats. The LD muscle from the YLB goats contained higher essential amino acid （P 〈 0.01）, total amino acid （P 〈 0.01）, and some individual amino acid （P 〈 0.05） than those from the hybrid goats. The concentration of unsaturated fatty acid （USFA） of LD muscle from the N × YLB hybrid goats was significantly higher than the other two goat breeds （P〈0.05） but did not differ between the other two goat breeds （P〉0.05）. The YLB goats had significantly higher （P〈0.05） concentrations of oleic acid （C18：1） and linolenic acid （C18：3） of LD muscle than the hybrid goats, had significantly higher （P 〈 0.05） proportion of mono-unsaturated （Sum for C 16：1 and C 18：1） than the B ×YLB hybrid goats, and tended to be higher than the N × YLB hybrid goats （P 〉 0.05）. In contrast, the proportion of poly-unsaturated in the YLB goats was significantly lower （P 〈 0.05） than that in the hybrid goats.

Dietary isoleucine affects muscle fatty acid and amino acid profiles through regulating lipid metabolism and autophagy in hybrid catfish(Pelteobagrus vachelli ♀×Leiocassis longirostris ♂)

The present study explored the impacts of Ile on muscle fatty acid and amino acid profiles,lipid metabolism,and autophagy in hybrid catfish.Seven isonitrogenous(387.8 g/kg protein)semi-purified diets were formulated to contain 5.0(control),7.5,10.0,12.5,15.0,17.5,and 20.0 g Ile/kg diet respectively.The fish(initial weight of 33.11±0.09 g)were randomly assigned to 7 groups for a 56-day trial.Each group has 3 replicates with 30 fish per replicate,fed at 08:00 and 18:00 each day.Results showed that muscle protein and lipid,C14:0,C18:0,C22:0,C14:1,C18:1n-9,polyunsaturated fatty acid(PUFA),Arg,Ile,Ala,Cys,Gly,Tyr,essential amino acid(EAA),and total amino acid(TAA)contents and flavor amino acid(FAA)/TAA in muscle had positive linear and/or quadratic responses to dietary Ile levels(P<0.05).Fatty acid synthase(FAS),stearoyl-Co A desaturase(SCD),acetyl-Co A carboxylase(ACC),and lipoprotein lipase(LPL)activities had positive linear and/or quadratic responses,but carnitine palmitoyl transferase 1(CPT1)activity had a negative response with increasing dietary Ile levels(P<0.05).The m RNA expressions of FAS,SCD,ACC,LPL,fatty acid binding protein 4(FABP4),FATP1,sterol response element-binding protein 1c(SREBP-1c),sequestosome 1(SQSTM1),and adenosine 5’-monophosphateactivated protein kinase(AMPK)had positive linear and/or quadratic responses to dietary Ile levels(P<0.05).The m RNA expressions of hormone-sensitive lipase(HSL),CPT1,peroxisome proliferatoractivated receptor a(PPARa),PPARγ,uncoordinated 51-like kinase 1(ULK1),beclin1(Becn1),autophagy-related protein 9a(Atg9a),Atg4b,Atg7,autophagy marker light chain 3 B(LC3B),and SQSTM1in muscle had negative linear and/or quadratic responses to dietary Ile levels(P<0.05).The p-AMPK and ULK1 protein levels,and p-AMPK/AMPK were decreased by 12.5 g Ile/kg in the diet(P<0.05).Finally,SQSTM1 protein level had the opposite effect(P<0.05).The above results indicate that dietary Ile improves fish muscle fatty acid and amino acid profiles potentially via respectively regulating lipid metabolism and autophagy.The Ile requirement of hybrid catfish(33 to 72 g)were estimated to be 12.63,13.77,13.75,11.45,10.50,12.53 and 12.21 g/kg diet based on the regression analysis of protein,lipid,SFA,PUFA,FAA,EAA,and TAA muscle contents,respectively.

Effects of fermented protein feed on the growth performance of pond-raised crab

This study aimed to elucidate the effect of a pellet feed containing fermented proteins on pond-raised Chinese mitten crabs,Eriocheir sinensis in a 7-month crab feeding experiment in Gucheng Lake,Jiangsu province,China.The results showed that fermented protein could significantly increase mean weight gain,crab size and total yield compared with control group.Moreover,the mean weight of male crabs and the number of large-sized male crabs improved over those of the control group.However,feed efficiency ratio did not differ significantly between the two groups.The amino acid content in the muscles of the female crabs of both the groups was higher than that in the muscles of the male crabs.The present study suggests that fermented compound protein may be one kind of potential protein sources for E.sinensis.