Effects of improved amino acid balance diet on lysine mammary utilization, whole body protein turnover and muscle protein breakdown on lactating sows

Background The study objective was to test the hypothesis that low crude protein(CP)diet with crystalline amino acids(CAA)supplementation improves Lys utilization efficiency for milk production and reduces protein turnover and muscle protein breakdown.Eighteen lactating multiparous Yorkshire sows were allotted to 1 of 2 isocaloric diets(10.80 MJ/kg net energy):control(CON;19.24%CP)and reduced CP with“optimal”AA profile(OPT;14.00%CP).Sow body weight and backfat were recorded on d 1 and 21 of lactation and piglets were weighed on d 1,14,18,and 21 of lactation.Between d 14 and 18,a subset of 9 sows(CON=4,OPT=5)was infused with a mixed solution of 3-[methyl-2H3]histidine(bolus injection)and[13C]bicarbonate(priming dose)first,then a constant 2-h[13C]bicarbonate infusion followed by a 6-h primed constant[1-13C]lysine infusion.Serial blood and milk sampling were performed to determine plasma and milk Lys enrichment,Lys oxidation rate,whole body protein turnover,and muscle protein breakdown.Results Over the 21-d lactation period,compared to CON,sows fed OPT had greater litter growth rate(P<0.05).Compared to CON,sows fed OPT had greater efficiency of Lys(P<0.05),Lys mammary flux(P<0.01)and whole-body protein turnover efficiency(P<0.05).Compared to CON,sows fed OPT tended to have lower whole body protein breakdown rate(P=0.069).Muscle protein breakdown rate did not differ between OPT and CON(P=0.197).Conclusion Feeding an improved AA balance diet increased efficiency of Lys and reduced whole-body protein turnover and protein breakdown.These results imply that the lower maternal N retention observed in lactating sows fed improved AA balance diets in previous studies may be a result of greater partitioning of AA towards milk rather than greater body protein breakdown.

Low crude protein formulation with supplemental amino acids for its impacts on intestinal health and growth performance of growing-finishing pigs

Background Low crude protein(CP)formulations with supplemental amino acids(AA)are used to enhance intestinal health,reduce costs,minimize environmental impact,and maintain growth performance of pigs.However,extensive reduction of dietary CP can compromise growth performance due to limited synthesis of non-essential AA and limited availability of bioactive compounds from protein supplements even when AA requirements are met.Moreover,implementing a low CP formulation can increase the net energy(NE)content in feeds causing excessive fat deposition.Additional supplementation of functional AA,coupled with low CP formulation could further enhance intestinal health and glucose metabolism,improving nitrogen utilization,and growth performance.Three experiments were conducted to evaluate the effects of low CP formulations with supplemental AA on the intestinal health and growth performance of growing-finishing pigs.Methods In Exp.1,90 pigs(19.7±1.1 kg,45 barrows and 45 gilts)were assigned to 3 treatments:CON(18.0%CP,supplementing Lys,Met,and Thr),LCP(16.0%CP,supplementing Lys,Met,Thr,Trp,and Val),and LCPT(16.1%CP,LCP+0.05%SID Trp).In Exp.2,72 pigs(34.2±4.2 kg BW)were assigned to 3 treatments:CON(17.7%CP,meeting the requirements of Lys,Met,Thr,and Trp);LCP(15.0%CP,meeting Lys,Thr,Trp,Met,Val,Ile,and Phe);and VLCP(12.8%CP,meeting Lys,Thr,Trp,Met,Val,Ile,Phe,His,and Leu).In Exp.3,72 pigs(54.1±5.9 kg BW)were assigned to 3 treatments and fed experimental diets for 3 phases(grower 2,finishing 1,and finishing 2).Treatments were CON(18.0%,13.8%,12.7%CP for 3 phases;meeting Lys,Met,Thr,and Trp);LCP(13.5%,11.4%,10.4%CP for 3 phases;meeting Lys,Thr,Trp,Met,Val,Ile,and Phe);and LCPG(14.1%,12.8%,11.1%CP for 3 phases;LCP+Glu to match SID Glu with CON).All diets had 2.6 Mcal/kg NE.Results In Exp.1,overall,the growth performance did not differ among treatments.The LCPT increased(P<0.05)Claudin-1 expression in the duodenum and jejunum.The LCP and LCPT increased(P<0.05)CAT-1,4F2hc,and B0AT expressions in the jejunum.In Exp.2,overall,the VLCP reduced(P<0.05)G:F and BUN.The LCP and VLCP increased(P<0.05)the backfat thickness(BFT).In Exp.3,overall,growth performance and BFT did not differ among treatments.The LCPG reduced(P<0.05)BUN,whereas increased the insulin in plasma.The LCP and LCPG reduced(P<0.05)the abundance of Streptococcaceae,whereas the LCP reduced(P<0.05)Erysipelotrichaceae,and the alpha diversity.Conclusions When implementing low CP formulation,CP can be reduced by supplementation of Lys,Thr,Met,Trp,Val,and Ile without affecting the growth performance of growing-finishing pigs when NE is adjusted to avoid increased fat deposition.Supplementation of Trp above the requirement or supplementation of Glu in low CP formulation seems to benefit intestinal health as well as improved nitrogen utilization and glucose metabolism.

Reduced protein diet with near ideal amino acid profile improves energy efficiency and mitigate heat production associated with lactation in sows

Background:The study objective was to test the hypothesis that 1)lowering dietary crude protein(CP)increases dietary energetic efficiency and reduces metabolic heat associated with lactation,and 2)excessive dietary leucine(Leu)supplementation in a low CP diet decreases dietary energetic efficiency and increases metabolic heat associated with lactation.Methods:Fifty-four lactating multiparous Yorkshire sows were allotted to 1 of 3 isocaloric diets(10.80 MJ/kg net energy):1)control(CON;18.75%CP),2)reduced CP with a near ideal or optimal AA profile(OPT;13.75%CP)and 3)diet OPT with excessive Leu(OPTLEU;14.25%CP).Sow body weight and backfat were recorded on day 1 and 21 of lactation and piglets were weighed on day 1,4,8,14,18,and 21 of lactation.Energy balance was measured on sows during early(day 4 to 8)and peak(day 14 to18)lactation,and milk was sampled on day 8 and 18.Results:Over 21-day lactation,sows fed OPT lost body weight and body lipid(P<0.05).In peak lactation,sows fed OPT had higher milk energy output(P<0.05)than CON.Sows fed OPTLEU tended(P=0.07)to have less milk energy output than OPT and did not differ from CON.Maternal energy retention was lower(P<0.05)in OPT and OPTLEU compared to CON sows,and did not differ between OPTLEU and OPT sows.Sows fed OPT had higher(P<0.05)apparent energy efficiency for milk production compared to CON.Heat production associated with lactation was lower(P<0.05)or tended to be lower(P=0.082),respectively,in OPT and OPTLEU compared to CON sows.Conclusion:The OPT diet,in peak lactation,improved dietary energy utilization for lactation due to less urinary energy and metabolic heat loss,and triggered dietary energy deposition into milk at the expense of maternal lipid mobilization.Leucine supplementation above requirement may reduce dietary energy utilization for lactation by decreasing the energy partitioning towards milk,partially explaining the effectiveness of OPT diet over CON diets.

Progress of amino acid nutrition for diet protein reduction in poultry

There is growing interest among nutritionists in feeding reduced protein diets to broiler chickens.Although nearly a century of research has been conducted providing biochemical insights on the impact of reduced protein diets for broilers,practical limitation still exists.The present review was written to provide insights on further reducing dietary protein in broilers.To construct this review,eighty-nine peer reviewed manuscripts in the area of amino acid nutrition in poultry were critiqued.Hence,nutritional research areas of low protein diets,threonine,glycine,valine,isoleucine,leucine,phenylalanine,histidine,and glutamine have been assessed and combined in this text,thus providing concepts into reduced protein diets for broilers.In addition,linkages between the cited work and least cost formation ingredient and nutrient matrix considerations are provided.In conclusion,practical applications in feeding reduced protein diets to broilers are advancing,but more work is warranted.

Effects of Low Protein Diets Supplemented with Ami-no Acids on Production Performance,Carcass Qual-ity and Input-output Ratio of Pigs

[ Objectives ] To study the effects of low-protein diets supplemented with amino acids on the production performance, carcass quality and input-output ratio of fattening pigs and growing-finishing pigs. [ Methods] Two studies were conducted on fattening pigs and growing pigs respectively. Pigs in two experimental groupswere fed with low-protein diets supplemented with amino acids and normal diets respectively, and the initial weight, final weight, feed consumption and car- cass index of the tested pigs were measured. [ Results] The average final weight of fattening pigs in test group was 2.4 kg lower than that in control group, while the difference was not significant （P 〉 0.05 ）. The average daily gain of fattening pigs in test group was 60 g lower than that in control group, indicating that low protein diets had a tendency to decrease the growth rate （P 〉 0.05 ）, and reduction of daily weight gain in low protein diet pigs reached 7.6%. The development of pigs in low protein diet group was poor, however, the difference was not significant. Carcass backfat thickness in low-protein diet group was slightly higher than that in control group, the difference was significant （ P 〈 0.05 ）. There was no significant difference in input-output ratio between low-protein diet group and control group. Finalweight of growing-finishing pigs in low-protein diet group was 3.22 % lower than that in control group, the average daily weight gainwas 6.91% lower than that in control group, feed intake in test group was 5.48% lower than that in control group, and difference between the two treatments was significant （P 〈 0.05 ）. Feed meat ratio in low-protein diet group improved, however, the difference was not significant（P 〉0.05）. [ Conclusions] Production performance of the pigs would be decreasedand the input-output ratio could not be improvedwhen the adding contents of crude protein in diets was reduced 3% -4%. Therefore, it is recommended that the crude protein level should be enough when pigs were fed with low-protein diets.

Dietary branched-chain amino acids modulate the dynamics of calcium absorption and reabsorption in proteinrestricted pigs

Background:Very low-protein(VLP)diets negatively impact calcium(Ca)metabolism and absorption.The objective of this study was to investigate the effect of supplemental branched-chain amino acids(BCAA)and limiting amino acids(LAA)on Ca digestibility,absorption and reabsorption in pigs fed with VLP diets.Forty-eight piglets were assigned to six treatments:positive control(PC),negative control(NC),and NC containing LAA 25%,LAA 50%,LAA+BCAA 25%(LB25)and LAA+BCAA 50%(LB50)more than recommendations.Results:Relative to PC or NC,LB25 and LB50 had higher digestibility of Ca and plasma Ca and phosphorus(P),but lower plasma vitamin D3.LB50 tended to increase vitamin D receptor transcript and protein in the gut,but decreased mRNA or protein abundance of parathyroid hormone 1 receptor(PTH1R),calbindin 1(CALB1),cytochrome P450 family 27 subfamily B member 1 and occludin in small intestine.LB50 increased the transcript of cytochrome P450 family 24 subfamily A member 1 and PTH1R but decreased the transcript of transient receptor potential cation channel subfamily V member 5,CALB1 and solute carrier family 17 member 4 in kidney.Conclusion:Overall,BCAA increased Ca digestibility through regulating the transcellular and paracellular Ca absorption in the gut and reabsorption in kidney during protein restriction.

Influence of Varying Crude Protein Levels and Balanced Amino Acids on the Performance and Haematological Characteristics of Laying Hens at the Second Phase of Production

Varying levels of dietary crude proteins and balanced amino acids were fed to layers for a period of eight weeks starting from the twenty-sixth week of age of birds and six weeks into egg production. Effects on performance and haematological characteristics were investigated at this second phase of production. Sixty Black Nera hens were randomly allotted into four (4) dietary treatments, containing the following levels of crude protein 14%, 15%, 16%, 17% and the metabolizable energy was iso-caloric for each treatment. The results showed that there were no significant differences (P > 0.05) observed for lymphocyte, Haemoglobin (Hb), Packed Cell Volume (PCV), Red Blood Cell (RBC) and White Blood Cell (WBC), these haematological parameters were within the range for healthy birds. Thus crude protein level of 14% can be used in diets of layers at the second phase of production provided that adequate amino acids are given, without adverse effect on egg laying, feed intake and measured blood parameters.

Improving the Dietary Protein Quality by Amino Acid Fortification with a High Inclusion Level of Micro Algae (<i>Spirulina platensis</i>) or Insect Meal (<i>Hermetia illucens</i>) in Meat Type Chicken Diets

The objective of this study was to measure protein quality parameters (PPV, NPU and NPUstd) of chicken diets with complete substitution of soybean meal (SBM) by Spirulina meal (SM) or partly defatted Hermetia meal (HM). N balance experiments were based on the quantitative excreta collection method, divided into starter period (10 - 20 d) and grower period (25 - 35 d). The study utilized 70 all male meat type chicken (Ross 308). Data assessment applied the exponential N utilization model of the “Goettingen approach”. The control diet was based on wheat, corn and SBM. In four experimental diets SBM was completely substituted by SM or HM, but fortified with feed amino acids (AA) both on a basic level of supplementation (Lys and Met added equal to the control diet) and on an extended level (Lys, Met, Thr, Arg, Val, Ile, His added). At a basic level of AA supplementation, complete replacement of SBM by SM or HM in chicken diets depressed dietary protein quality significantly (p 0.05). However, the extended level of AA supplementation improved protein quality parameters of the diets with both of the alternative proteins significantly (p < 0.05), but still generally not on par with the control diet. The observed responses were accentuated when the well-known effect of N intake on protein utilization was eliminated through the standardization of N intake by application of the “Goettingen approach”.

Advances in low-protein diets for swine

Recent years have witnessed the great advantages of reducing dietary crude protein(CP) with free amino acids(AA)supplementation for sustainable swine industry, including saving protein ingredients, reducing nitrogen excretion, feed costs and the risk of gut disorders without impairing growth performance compared to traditional diets. However, a tendency toward increased fatness is a matter of concern when pigs are fed low-protein(LP) diets. In response, the use of the net energy system and balanced AA for formulation of LP diets has been proposed as a solution. Moreover, the extent to which dietary CP can be reduced is complicated. Meanwhile, the requirements for the first five limiting AA(lysine, threonine, sulfur-containing AA, tryptophan, and valine) that growing-finishing pigs fed LP diets were higher than pigs fed traditional diets, because the need for nitrogen for endogenous synthesis of non-essential AA to support protein synthesis may be increased when dietary CP is lowered. Overall, to address these concerns and give a better understanding of this nutritional strategy, this paper reviews recent advances in the study of LP diets for swine and provides some insights into future research directions.

Effect of dietary near ideal amino acid profile on heat production of lactating sows exposed to thermal neutral and heat stress conditions

Background:Reduced protein diet manifested potential to mitigate heat production based on the concept of ideal amino acid profile.The hypothesis of this study was that lactating sows fed a low crude protein(LCP)diet with supplemental amino acid produce less heat compared to those fed a high crude protein(HCP)diet under both thermal neutral(TN)and heat stress(HS)conditions.Methods:Thirty-two lactating sows were allotted to HCP(193 g CP/kg)and LCP(140 g CP/kg)diets under thermal neutral(TN,21±1.5°C)or cycling heat stress(HS,32±1.5°C daytime and 24±1.5°C nighttime)conditions.Diets contained 0.90%SID lysine and 10.8 MJ/kg net energy.Positive pressure indirect calorimeters were used to measure gas exchange in individual sows with litters,and individual piglets on days 4,8,14 and 18.Sow and litter weights were recorded on days 1,10 and 21.Results:Sow total heat production(THP)was calculated by subtracting litter THP from sow+litter THP based on BW0.75.Sow BW and body protein(BP)loss was greater for LCP diet compared to HCP diet in peak lactation(P<0.05 and P<0.01,respectively)and throughout the entire lactation period(P<0.05 and P=0.056,respectively)under HS conditions.Heat-stressed sows fed HCP diet had higher(P<0.05)rectal temperature at 13:00(P<0.05)and 19:00(P<0.01),and higher respiration rate at 07:00(P<0.05),13:00(P<0.05)and 19:00(P<0.05)compared to TN sows fed HCP diet.In sows fed LCP diet,those under HS tended to have higher(P=0.098)rectal temperature at 13:00 and had higher(P<0.05)respiration rate at 07:00,13:00 and 19:00 compared to TN sows.The relationship between daily THP and days in lactation of sows fed LCP diet was quadratic(P<0.05),with an ascending trend until day 14 and a descending trend from days 14 to 18.Sows fed LCP diet had lower daily THP at day 18(P<0.001)compared to those fed the HCP diet under HS conditions.Conclusion:Reduction in THP in sows fed LCP diet was largely associated with THP on day 18 of lactation under HS conditions.Feeding LCP diets alleviated the increased body temperature in sows under HS conditions throughout lactation,which was accompanied by a reduction in respiration rate.Total heat production is associated with days in lactation,in particular under HS conditions with THP appearing to peak between days 14 and 18.

Evaluation of the Protein Requirement in Chinese Young Adults Using the Indicator Amino Acid Oxidation Technique

Objective To accurately calculate the protein requirements in Chinese young adults using the indicator amino acid oxidation technique. Methods Nine women and ten men received a restricted daily level of protein intake （0.75, 0.82, 0.89, 0.97, and 1.05 g/kg）, along with L-[1-13C]-Ieucine. Subjects＇ protein requirement was determined by a biphasic linear regression crossover analysis of F13C02 data. In doing so, a breakpoint at the minimal rate of appearance of 13C02 expiration specific to each level of dietary protein was identified. This trial was registered with the Chinese clinical trial registry as ChiCTR-ONC-11001407. Results The Estimated Average Requirement （EAR） and the Recommended Nutrient Intake （RNI） of protein for healthy Chinese young adults were determined to be 0.87 and 0.98 g/（kg.d）, respectively, based on the indicator amino acid oxidation technique. Conclusion The EAR and RNI of mixed protein are 5% and 16% that are lower than the current proposed EAR and RNI {0.92 and 1.16 g/（kg.d）, respectively）, as determined by the nitrogen balance method. The respective EAR and RNI recommendations of 0.87 and 0.98 g/（kg.d） of mixed protein are estimated to be reasonable and suitable for Chinese young adults.

Estimate of Amino Acid Balance in Nutrition

A new chemical index-imbalance degree (IBD), was proposed on the basis of cluster analysis in multivariate statistical analysis to estimate the extent of amino acid balance in protein. The range of IBD is between 0 and 1, successively corresponding to complete balance and entire imbalance for the amino acid profile of a sample. The amino acid increment model of IBD belongs to an asymmetrical maximum-type, and there is a high correlation between IBD and coefficient of variation (CV). The nutritional value of individual feed can be ranked and clustered according to its IBD; and by calculating the IBD of amixed sample with two or more feedstuffs, it is Possible theoretically to predict whether a synergetic. pheno men on exists and when an optimal mutual complement can happen. If the conceptive frame of IBD extended, it can be used to study the balance of nutrients besides amino acids, and is helpful to realize the automatic distinction and selection in diet formulating.

Protein tolerance to standard and high protein meals in patients with liver cirrhosis

To investigate the plasma amino acid response and tolerance to normal or high protein meals in patients with cirrhosis. METHODSThe plasma amino acid response to a 20 g mixed protein meal was compared in 8 biopsy-proven compensated cirrhotic patients and 6 healthy subjects. In addition the response to a high protein meal (1 g/kg body weight) was studied in 6 decompensated biopsy-proven cirrhotics in order to evaluate their protein tolerance and the likelihood of developing hepatic encephalopathy (HE) following a porto-caval shunt procedure. To test for covert HE, the “number connection test” (NCT) was done on all patients, and an electroencephalogram was recorded in patients considered to be at Child-Pugh C stage. RESULTSThe changes in plasma amino acids after a 20 g protein meal were similar in healthy subjects and in cirrhotics except for a significantly greater increase (P < 0.05) in isoleucine, leucine and tyrosine concentrations in the cirrhotics. The baseline branched chain amino acids/aromatic amino acids (BCAA/AAA) ratio was higher in the healthy persons and remained stable-but it decreased significantly after the meal in the cirrhotic group. After the high protein meal there was a marked increase in the levels of most amino acids, but only small changes occurred in the levels of taurine, citrulline, cysteine and histidine.The BCAA/AAA ratio was significantly higher 180 and 240 min after the meal. Slightly elevated basal plasma ammonia levels showed no particular pattern. Overt HE was not observed in any patients. CONCLUSIONPatients with stable liver disease tolerate natural mixed meals with a standard protein content. The response to a high protein meal in decompensated cirrhotics suggests accumulation of some amino acids but it did not precipitate HE. These results support current nutritional guidelines that recommend a protein intake of 1.2-1.5 g/kg body weight/day for patients with cirrhosis.

Branched-chain amino acids partially recover the reduced growth of pigs fed with protein-restricted diets through both central and peripheral factors

The objective of this study was to assess the growth efficiency of pigs fed with protein-restricted diets supplemented with branched-chain amino acids(BCAA)and limiting amino acids(LAA)above the rec-ommended levels.Following 2 weeks of adaptation,48 young barrows were weight matched and randomly assigned to 6 treatments(8 pigs/treatment)for 4 weeks:positive control(PC)with standard protein,negative control(NC)with very low protein containing LAA(i.e.,Lys,Met,Thr and Trp)at rec-ommended levels,and NC containing LAA 25%(L25),LAA 50%(L50),LAA+BCAA(i.e.,Leu,Ile and Val)25%(LB25)and LAA+BCAA 50%(LB50)more than recommendations.Feed intake(FI)and body weight(BW)were measured daily and weekly,respectively.At week 6,blood samples were collected,all pigs euthanized and tissue samples collected.The data were analyzed by univariate GLM or mixed procedure(SPSS)and the means were separated using paired Student's t-test followed by Benjamini-Hochberg correction.Relative to PC,NC had decreased FI,BW,unsupplemented plasma essential amino acids,serum insulin-like growth factor-I(IGF-I)and hypothalamic neuropeptide Y(NPY)(P<0.01).Compared to NC,L25 or L50,LB50 had increased BW and serum IGF-I and decreased plasma serotonin and both LB25 and LB50 had higher FI,plasma BCAA,hypothalamic 5-hydroxytryptamine-receptor 2A and NPY and jejunal 5-hydroxytryptamine-receptor 7(P<0.01).Overall,supplementation of protein-restricted diets with increased levels of dietary BCAA partially recovered the negative effects of these diets on growth through improved IGF-I concentration and FI,which was associated with changed expression of serotonin receptors,blood AA and hypothalamic NPY.

Effects of reducing dietary protein on the expression of nutrition sensing genes(amino acid transporters) in weaned piglets

The effects of crude protein（CP） levels in the diet on the m RNA expression of amino acid（AA） transporters were studied in a 45-d trial. Eighteen piglets with an initial body weight（BW） of 9.57 kg were assigned to three groups（14%, 17%, and 20% CP in the diet） in a completely randomized design（six replicates per treatment）. Diets were supplemented with crystalline AA to achieve equal standardized ileal digestible contents of Lys, Met plus Cys, Thr, and Trp, and were provided ad libitum. After 45 d, all piglets were slaughtered to collect small intestine samples. Compared with the values in the 14% CP group, the expressions of ASCT2, 4F2 hc, and ATB0 m RNA in the jejunum were increased by 23.00%, 12.00%, 6.00% and 48.00%, 47.00%, 56.00% in the 17% and 20% CP groups, respectively. These results indicate that a 14% CP diet supplemented with crystalline AA may not transport enough AA into the body and maintain growth performance of piglets. However, a reduction of dietary 17% CP may reduce the excretion of nitrogen into the environment while supporting the development of piglets. Therefore, the 17% CP level is more suitable than 14% CP level.

Low Light During Grain Filling Stage Deteriorates Rice Cooking Quality, but not Nutritional Value

To investigate the effect of low light （LL, 50% natural light） during grain filling （GF） stage on rice transamination, amino acid （AA） accumulation, nutritional value, and cooking quality in three different rice genotypes, transaminase activities and AA levels in grains during GF stage and the traits that significantly affected rice quality （physical appearance, cooking quality, and nutritional value） were analyzed. LL did not disturb transamination in rice grains during GF stage, as minimal impact was found on alanine and aspartate transaminase activities. Nevertheless, most AAs in caryopses, including lysine and threonine, increased in response to LL, except for sulfur-containing AAs. These results suggest that AA metabolism and accumulation in rice grains were rarely suppressed by LL during GF stage. Rice nutritional ingredients at harvest, such as major protein components including glutelin and most important essential amino acids （EAAs） including lysine and threonine, increased significantly in response to LL, whereas most protein and EAA ratios were rarely affected. However, LL markedly affected physical appearance of rice grains by reducing brown rice rate, milled rice rate, and 1000-grain weight and increasing the chalkiness rate. In addition, cooking qualities decreased in response to LL, while breakdown values and amylose levels decreased and setback values increased. We concluded that LL during GF stage decreased the cooking quality of rice, but could potentially improve the nutritional value of rice.

Assessment of limiting dietary amino acids in broiler chickens offered reduced crude protein diets

As lowering crude protein(CP)in poultry diets continues to minimize amino acid excess,it is important to understand the limiting order of amino acids and the impact of their deficiencies.Therefore,a pair of experiments were conducted to observe the effects of individual amino acid deletions on growth performance,carcass traits,and nutrient utilization.Both experiments involved 3 control diets based on wheat and soybean meal,including a 210.0 g/kg CP industry control(IC),186.7 g/kg CP positive control(PC)supplemented with feed-grade amino acids to match the IC amino acid profile,186.7 g/kg CP negative control(NC)with reducing N corrected apparent metabolizable energy(AMEN)by 0.5 MJ/kg and removing feed-grade amino acids beyond L-Lys-HCl,DL-Met,and L-Thr from PC.Ten deletion diets where the following supplemented amino acids were individually removed from the PC:Val,Ile,Leu,Trp,Arg,His,Phe t Tyr,glycine equivalence(Glyequi),Pro,and Energy(0.5 MJ/kg reduction in AMEN of the PC).All diets were formulated to contain similar concentrations of digestible Lys,total sulfur amino acid(TSAA)and Thr.Experimental diets were offered to broiler chickens from 15 to 22 d postehatch in a cage study(Exp.1)to gain digestibility and nutrient utilization data;whereas they were offered from 15 to 35 d post ehatch in a floor-pen study(Exp.2)to gain performance and carcass yield data.The removal of supplemented Val,Arg,and Ile resulted in reduction on broiler performance(P<0.05),and the removal of Val,Arg,Ile,and Glyequi negatively influenced carcass traits(P<0.05).Results from both experiments indicate that Val and Arg are co-limiting in wheat-soybean meal diets,but that Ile and Glyequi may potentially limit breast and thigh development.

Supplementation of branched-chain amino acids in protein-restricted diets modulates the expression levels of amino acid transporters and energy metabolism associated regulators in the adipose tissue of growing pigs

This experiment was conducted to investigate the effects of branched-chain amino acids(BCAA)supplemented in protein-restricted diets on the growth performance and the expression profile of amino acid transporters and energy metabolism related regulators in the white adipose tissue(WAT)of different regional depots including dorsal subcutaneous adipose(DSA) and abdominal subcutaneous adipose(ASA), A total of 24 crossbred barrows(7.40 ± 0.70 kg) were randomly divided into 4 groups and were fed the following isocaloric diets for 33 days: 1) a recommended adequate protein diet(AP, 20% CP, as a positive control); 2) a low protein diet(LP, 17% CP); 3) the LP diet supplemented with BCAA(LP + B, 17% CP) to reach the same level of the AP diet group; 4) the LP diet supplemented with 2 times the amount of BCAA(LP + 2B, 17% CP). The daily gain and daily feed intake of the LP diet group were the lowest among all the treatments(P < 0.01). The feed conversion was improved markedly in the group of LP + B compared with the LP diet group(P < 0.05). No significant difference was noted for the serum biochemical parameter concentrations of glucose, triglyceride, nonesterified fatty acid and insulin among the groups(P > 0.05). Moreover, BCAA supplementation down-regulated the expression levels of amino acid transporters including L-type amino acid transporter 1 and sodium-coupled neutral amino acid transporter 2 in DSA, but up-regulated the expression level of Ltype amino acid transporter 4 in ASA(P < 0.05), Meanwhile, the energy sensor AMP-activated protein kinase α was activated in the DSA of pigs fed LP diet and in the ASA of the pigs fed AP or LP + 2B diets(P < 0.05). The mRNA expression profile of the selected mitochondrial component and mitochondrial biogenesis associated regulators in DSA and ASA also responded differently to dietary BCAA supplementation. These results suggested that the growth performance of growing pigs fed protein restricted diets supplemented with BCAA could catch up to that of the pigs fed AP diets. The results also partly demonstrated that the regulation mechanisms of BCAA are different in the adipose tissues of different depots.

典型饲用氨基酸的太赫兹光谱检测与密度泛函理论指认分析

为探索用于畜禽饲喂低蛋白日粮的典型氨基酸太赫兹波段指纹特性及其与分子结构相关性,本文基于太赫兹时域光谱技术和密度泛函理论(DFT)对蛋氨酸等6种饲用氨基酸开展了实验测量和理论振动计算分析。首先,制备了氨基酸实验样本,测量了它们在0.5~2.0 THz的太赫兹吸收光谱,发现:蛋氨酸在1.48和1.54 THz、赖氨酸在0.95和1.67 THz、色氨酸在1.2和1.4 THz、苏氨酸在1.42 THz、组氨酸在1.4 THz、异亮氨酸在1.41和1.51 THz处呈现明显吸收特性;然后,利用GaussView软件构建了6种氨基酸单分子结构,应用DFT理论的B3LYP杂化泛函方法,结合6-311G(d,p)基组优化结构,计算获得其太赫兹波段的频谱特征,发现:蛋氨酸在1.51 THz、赖氨酸在0.89和1.68 THz、色氨酸在0.67和1.39 THz、苏氨酸在1.4 THz、组氨酸在1.4 THz、异亮氨酸在1.56和1.75 THz处有一定吸收,与实际实验测量吸收峰位基本吻合;最后,利用Gaussian软件分析了6种氨基酸在0.5~2.0 THz波段各吸收峰处的振动模式,发现:蛋氨酸1.51 THz处吸收峰源自其甲基团的面内摇摆振动;赖氨酸0.89和1.68 THz处吸收峰源自其羧基官能团的旋转和氨基官能团的面内摇摆振动;色氨酸1.39 THz处吸收峰源自其羧基官能团的面外弯曲振动;苏氨酸1.4 THz处吸收峰源自其羧基官能团的面外弯曲和氨基官能团的面内摇摆振动;组氨酸1.4 THz处吸收峰源自其氨基官能团的面内摇摆和整体摇摆振动;异亮氨酸1.56 THz处吸收峰源自其甲基团和氨基官能团的整体摇摆和羧基官能团的面外摇摆振动、1.75 THz处吸收峰源自其甲基团的整体摇摆和羧基官能团的面外摇摆振动。该研究为利用太赫兹光谱技术开展典型饲用氨基的快速定性定量研究提供理论参考。

畜禽豆粕减量替代技术研究进展

一直以来,我国畜牧业对进口豆粕的依存度较高,近年来随着国际环境、贸易政策和全球气候的变化,豆粕的供应日益紧张,价格居高不下,制约了我国饲料业和畜牧业的发展。为保障我国饲料粮的供给安全,农业农村部部署“提效减量、开源替代”任务,豆粕减量替代工作刻不容缓、意义重大。文章综述了当前畜禽养殖行业中豆粕减量替代技术的研究进展,以期为饲料行业的发展提供参考。