Standardized ileal digestibility of amino acids in soybean meal fed to non-pregnant and pregnant sows

Background Two studies were designed to determine standard ileal crude protein(CP)and amino acid(AA)digestibility of soybean meal(SBM)from different origins fed to non-pregnant and pregnant sows.Seven solvent-extracted SBMs from soybeans produced in the USA,Brazil,and China were selected.In Exp.1,eight different diets were created:a nitrogen(N)-free diet and 7 experimental diets containing SBM from different origins as the only N source.Eight non-pregnant,multiparous sows were arranged in an 8×8 Latin square design(8 periods and 8 diets).In Exp.2,the diet formula was the same as in Exp.1.Eight gestating sows(parity 3)were assigned to 4 different diets in a replicated 4×3 Youden square design(three periods and four diets)in mid-gestation and again in late-gestation stages.Results When fed to non-pregnant and late-gestating sows,the standardized ileal digestibility(SID)of CP and most AAs from different SBM were not significantly different(P>0.05).When fed to mid-gestating sows,the SID values for Arg,His,Lys,Phe,Cys,Gly,Ser,and Tyr in SBM 1 were lower than in SBM 4 and 5(P<0.05),whereas SID for Leu from SBM 5 was higher than in SBM 1 and 4(P<0.05).SID values for Ile,Ala,and Asp from SBM 4 were lower than in SBM 1 and 5(P<0.05).Sows had significantly greater SID values for Lys,Ala,and Asp during mid-gestation when compared with late-gestation stages(P<0.05).Mid-gestating sows had greater SID value for Val and lower SID value for Tyr when compared with non-pregnant and late-gestating sows(P<0.01),whereas non-pregnant sows had significantly greater SID value for Met when compared with gestating sows(P<0.01).Conclusions When fed to mid-gestating sows,the SID values for most AAs varied among SBM samples.The SID values for Lys,Met,Val,Ala,Asp,and Tyr in SBM were affected by sow gestation stages.Our findings provide a cornerstone for accurate SBM use in sow diets.

Effects of dietary oil sources and fat extraction methods on apparent and standardized ileal digestibility of fat and fatty acids in growing pigs

Background:There is a lack of data for the standardized ileal digestibility(SID) of fat and fatty acids in national feed databases.In addition,it is important to specify the procedures used for fat analyses.Therefore,an experiment was conducted to 1) determine the apparent ileal digestibility(AID) and SID of fat and fatty acids in ten different oil sources for growing pigs and to develop prediction equations for SID of fat based on fatty acid composition;and 2) compare the effect of the fat extraction methods on the calculated values for endogenous loss and digestibility of fat.Methods:Twenty-two barrows(initial body weight:32.1 ± 2.3 kg) were surgically fitted with a T-cannula in the distal ileum,and allotted to 1 of 11 experimental diets in a 4-period Youden Square design.A fat-free diet was formulated using cornstarch,soy protein isolate and sucrose.Ten oil-added diets were formulated by adding 6% of dietary oil sources to the fat-free diet at the expense of cornstarch.All diets contained 26% sugar beet pulp and 0.40% chromic oxide.Results:The endogenous loss of ether extract(EE) was lower than that of acid-hydrolyzed fat(AEE;P < 0.01).There were significant differences in the AID and SID of fat and saturated fatty acids across the dietary oil sources(P < 0.05).The SID of AEE for palm oil was lower than that of sunflower oil,corn oil,canola oil,rice oil and flaxseed oil(P < 0.01).The AID and SID of fat ranged from 79.65% to 86.97% and from 91.14% to 99.18%.Although the AID of EE was greater than that of AEE(P < 0.01),there was no significant difference in SID of EE and AEE except for palm oil.The ratio of unsaturated to saturated fatty acids(U/S) had a positive correlation with SID of fat(P < 0.05),whereas C16:0 and long chain saturated fatty acids(LSFA) were significant negatively correlated with SID of fat(P < 0.01).The best-fit equation to predict SID of fat was SID AEE = 102.75-0.15 × LSFA-0.74 × C18:0-0.03 × C18:1(Adjusted coefficient of determination = 0.88,P < 0.01).Conclusions:When calculating the SID of fat,the EE content of the samples can be analyzed using the direct extraction method,whereas the acid hydrolysis procedure should be used to determine the AID of fat.Fat digestibility of dietary oils was affected by their fatty acid composition,especially by the contents of C16:0,LSFA and U/S.

Determination of basal ileal endogenous losses and standardized ileal digestibility of amino acids in barley fed to growing pigs

Background： Basal ileal endogenous amino acid（AA） losses（IAAend） and standardized ileal digestibility（SID） values of cereal grains, such as barley, are apparently underestimated when determined according to the nitrogen（N）-free method. Regression analysis between the dietary apparent ileal digestible content（c AID） and total crude protein（CP） and AA can be considered as alternative approach to obtain more accurate values for IAAendand SID of AA in cereal grains.Methods： Eight hulled barley genotypes were used, with barley being the only source of CP and AA in the assay diets. The diets contained 95 % as-fed of these eight barley genotypes each, ranging in CP content between 109.1 and 123.8 g/kg dry matter（DM）. Nine ileally T-cannulated barrows, average body weight（BW） 30 ± 2 kg, were allotted to a row-column design comprising eight periods with 6 d each and nine pigs. On d 5 and the night of d 6 of every period, ileal digesta were collected for a total of 12 h. The IAAend and the SID were determined by linear regression analysis between c AID and total dietary CP and AA.Results： There exist linear relationships between cA ID and total CP and AA（P 〈 0.001）. The IAAend of CP, Lys, Met, Thr and Trp amounted to 35.34, 1.08, 0.25, 1.02 and 0.38 g/kg DM intake（DMI）, respectively, which are greater compared to average IAAend determined previously under N-free feeding conditions. The SID of CP, Lys, Met, Thr and Trp was 90,79, 85, 79 and 86 %, respectively, and was greater when compared to tabulated values. Moreover, these SID values were greater than those reported in literature, based on correction of apparent ileal digestibility（AID） of CP and AA for their IAAendvalues. Summarized, the results of the present regression analysis indicate greater IAAendin barley-based diets compared to those obtained by N-free feeding.Conclusions： For low-protein feed ingredients like barley the regression method may be preferred over correction of AID values for their IAAenddetermined under N-free feeding conditions, as intercepts and slopes of the linear regression equations between cA ID and total dietary CP and AA provide direct estimates of IAAendand SID of CP and AA in the presence of the assay feed ingredient.

Effects of Coated Methionine on the Growth Performance, Blood Biochemical Indices and Nutrient Apparent Ileal Digestibility in Broilers

[ Objective] This trial was conducted to study the effects of different coated methionines on the growth performance, blood biochemical indices and apparent ileal digestibility of amino acids in broilers. [ Method ] A total of 3 780 Cobb 500 broilers aged 18 days were randomly arranged into 7 groups with 3 replicates per group and 180 broilers per replicate. Control group （A） received the basal diet supplemented with O. 16% DL-me- thionine, and trial groups received the basal diets supplemented with 0.32% （ B）, 0.29% （ C）, 0.26% （ D）, 0.22% （ E）, 0.19% （F） and 0.16% （G） of coated methionine, and broilers were fed to the age of 42 days. ＂[ Result] The final weight, average daily gain and average daily feed intake of groups B and C were higher than those of the control group （ P〈0.05）, and the mortality of group B was lower than that of the control group （ P 〈0.05）, but there was no significant difference in all above indices between the other groups and the control group （P 〉 0.05）. Plasma GSH-Px activity of trial groups （ except group G） was higher than that of the control group （ P 〈 0.05）, and SOD activity of groups B and C were higher than that of group G （P 〈0.05）, but there were no significant differences in other blood biochemical indices among all groups （P 〉0.05）. There were no significant differences in apparent ileal digestibility of dry matter and crude protein between trial groups and the control group （ P 〉0.05 ）, and the apparent ileal digestibility of amino acids of trial groups was increased （P 〈0.05） or no change expect that the apparent ileal digestibility of many kinds of amino acids of group G was decreased compared with the control group （P〈0.05）. [ Concluslon~ The growth performance and apparent ileal digestibility of amino acids in broilers were increased with the rising supplementation of coated methionine, but the supplementation of 0.19% coated methionine can meet the needs of broilers, namely, coated methionine can be substituted for 60% DL-methionine in the diet, so DL-methio- nine can be saved up to 40%.

Methodological impact of starch determination on starch content and ileal digestibility of starch in grain legumes for growing pigs

Background： Grain legumes represent a valuable energy source in pig diets due to their high starch content. The present study was conducted to determine the content and apparent ileal digestibility（AID） of starch in different grain legume cultivars for pigs by means of both a polarimetric and enzymatic method for starch determination.Methods： Three experiments were conducted with six barrows each which were fitted with ileal T-cannulas. In total, 18 diets including six different cultivars of faba beans（Vicia faba L.） and peas（Pisum sativum L.）, five different cultivars of lupins（Lupinus luteus L., Lupinus angustifolius L.）, and one diet with a soybean meal（SBM） were fed.Results： The starch content of faba beans and peas was greater（P ＆lt; 0.05） when determined polarimetrically than enzymatically（438 vs. 345 g/kg dry matter（DM） in faba beans and 509 vs. 390 g/kg DM in peas, respectively）.Considerable lower starch contents were obtained in lupins and SBM, with 82 and 48 g/kg DM（analyzed polarimetrically） and ＆lt;1.1 and 3 g/kg DM（analyzed enzymatically）, respectively. Mean values for contents of neutral detergent fiber（NDF） and acid detergent fiber（ADF） in grain legumes ranged from 111 and 79 g/kg DM in peas to248 and 207 g/kg DM in lupins, respectively. Contents of condensed tannins in the colored flowered faba bean cultivars ranged from 2.1 to 7.4 g/kg DM. The AID of starch was greater（P ＆lt; 0.05） in pea than in faba bean cultivars,and using the polarimetric starch determination method resulted in greater（P ＆lt; 0.05） digestibility values than using enzymatic starch analysis（84 vs. 80% in faba beans and 86 vs. 83% in peas）. Moreover, AID of starch differed（P ＆lt; 0.05）within pea cultivars and starch digestibility in faba beans decreased linearly（P ＆lt; 0.05） as the content of condensed tannins increased. However, there was no relationship between contents of NDF and ADF and AID of starch in pea and faba bean cultivars.Conclusion： Both contents and AID of starch in grain legumes can vary as influenced by the analytical method used for starch determination. Generally, starch digestibility is greater when measured by polarimetric rather than enzymatic methods.

Oils with different degree of saturation:effects on ileal digestibility of fat and corresponding additivity and bacterial community in growing pigs

Background Oils are important sources of energy in pig diets.The combination of oils with different degree of saturation contributes to improve the utilization efficiency of the mixed oils and may reduce the cost of oil supplemented.An experiment was conducted to evaluate the effects of oils with different degree of saturation on the fat digestibility and corresponding additivity and bacterial community in growing pigs.Methods Eighteen crossbred(Duroc×Landrace×Yorkshire)barrows(initial body weight:29.3±2.8 kg)were surgically fitted with a T-cannula in the distal ileum.The experimental diets included a fat-free basal diet and 5 oil-added diets.The 5 oil-added diets were formulated by adding 6%oil with different ratio of unsaturated to saturated fatty acids(U:S)to the basal diet.The 5 oils were palm oil(U:S=1.2),canola oil(U:S=12.0),and palm oil and canola oil were mixed in different proportions to prepare a combination of U:S of 2.5,3.5 and 4.5,respectively.Results The apparent and standardized ileal digestibility(AID and SID)of fat and fatty acids increased linearly(P<0.05)as the U:S of dietary oils increased except for SID of fat and C18:2.The AID and SID of fat and fatty acids differed among the dietary treatments(P<0.05)except for SID of unsaturated fatty acids(UFA)and C18:2.Fitted one-slope broken-line analyses for the SID of fat,saturated fatty acids(SFA)and UFA indicated that the breakpoint for U:S of oil was 4.14(R^(2)=0.89,P<0.01),2.91(R^(2)=0.98,P<0.01)and 3.84(R^(2)=0.85,P<0.01),respectively.The determined SID of fat,C18:1,C18:2 and UFA in the mixtures was not different from the calculated SID of fat,C18:1,C18:2 and UFA.However,the determined SID of C16:0,C18:0 and SFA in the mixtures were greater than the calculated SID values(P<0.05).The abundance of Romboutsia and Turicibacter in pigs fed diet containing palm oil was greater than that in rapeseed oil treatment group,and the two bacteria were negatively correlated with SID of C16:0,C18:0 and SFA(P<0.05).Conclusions The optimal U:S for improving the utilization efficiency of mixed oil was 4.14.The SID of fat and UFA for palm oil and canola oil were additive in growing pigs,whereas the SID of SFA in the mixture of two oils was greater than the sum of the values of pure oils.Differences in fat digestibility caused by oils differing in degree of saturation has a significant impact on bacterial community in the foregut.

Total amino acid level affects the results of standardized ileal digestibility assays for feed ingredients for swine

It has been demonstrated that the fiber content of oilseed meals and total amino acids(AA)in distillers'grains products affects standardized ileal digestibility(SID)values from swine assays and that total protein concentration affects the AA digestibility in assays using chickens.This analysis was conducted to test the hypothesis that the total AA content of test samples affects the SID assay results.Databases containing total AA profiles and SID values of 20 feedstuffs commonly fed to pigs from 2 sources,AMINODat 5.0(Evonik Industries,2015)and the Nutrient Requirements of Swine,12th edition(NRC,2012)were used to compare AA concentration effects on standardized ileal digestibility coefficients.Databases were compared with AA and SID available in both data sets.The total AA values were similar for the 2 databases with an R2 of 0.979(P<0.001).The linear relationship between digestibility co-efficients from the 2 databases was highly significant,an R2 of 0.810(P<0.001).Both databases had increased SID values with increasing AA contents within and across feed ingredients.The SID=f(AA concentration)relationship was confirmed with an individual paper.Since SID,as typically measured,is a function of both digestion and absorption,both processes following MichaeliseMenten kinetics,SID=f(AA concentration)may simply be a natural phenomenon.Other reasons for the relationship were explored.Methods of estimating endogenous AA losses and misapplication statistical procedures may contribute to variation in results and at least partially explain why SID=f(AA concentration).

Effect of Bacillus subtilis and Bacillus licheniformis supplementation in diets with low-and high-protein content on ileal crude protein and amino acid digestibility and intestinal microbiota composition of growing pigs

Background： Bacillus spp. seem to be an alternative to antimicrobial growth promoters for improving animals＇ health and performance. However, there is little information on the effect of Bacillus spp. in combination with different dietary crude protein（CP） levels on the ileal digestibility and microbiota composition. Therefore, the objective of this study was to determine the effect of Bacillus spp. supplementation to low-（LP） and high-protein diets（HP） on ileal CP and amino acid（AA） digestibility and intestinal microbiota composition.Methods： Eight ileally cannulated pigs with an initial body weight of 28.5 kg were randomly allocated to a rowcolumn design with 8 pigs and 3 periods of 16 d each. The assay diets were based on wheat-barley-soybean meal with two protein levels： LP（14% CP, as-fed） and HP diet（18% CP, as-fed）. The LP and HP diets were supplemented with or without Bacil us spp. at a level of 0.04%（as-fed）. The apparent ileal digestibility（AID） and standardized ileal digestibility（SID） of CP and AA was determined. Bacterial community composition from ileal digesta was analyzed by Illumina amplicon sequencing and quantitative real-time PCR. Data were analyzed as a 2 × 2 factorial design using the GLIMMIX procedures of SAS.Results： The supplementation with Bacillus spp. did not affect both AID and SID of CP and AA in growing pigs.Moreover, there was no difference in AID of CP and AA between HP and LP diets, but SID of cystine, glutamic acid,glycine, and proline was lower（P 〈 0.05） in pigs fed the HP diets. The HP diets increased abundance of Bifidobacterium spp. and Lactobacillus spp.,（P 〈 0.05） and by amplicon sequencing the latter was identified as predominant genus in microbiota from HP with Bacillus spp., whereas dietary supplementation of Bacillus spp. increased（P 〈 0.05） abundance of Roseburia spp.Conclusions： The HP diet increased abundance of Lactobacillus spp. and Bifidobacterium spp.. The supplementation of Bacil us spp. resulted in a higher abundance of healthy gut associated bacteria without affecting ileal CP and AA digestibility, whereas LP diet may reduce the flow of undigested protein to the large intestine of pigs.

Effects of corn gluten feed inclusion at graded levels in a corn-soybean diet on the ileal and fecal digestibility of growing pigs

Background： This study aimed to determine the effect of the inclusion of corn gluten feed （CGF） on the apparent and standardized ileal digestibility of protein and amino acids and the apparent ileal and total tract digestibility of energy in growing pigs. The study was performed using 16 barrows （weight, 45.3 ±4.5 kg） that were fitted with a T cannula at the terminal ileum. There were four treatments： a corn-soybean diet without CGF and three corn-soybean diets containing increasing levels of CGF （65, 130, and 195 g/kg）. Data were analyzed according to a randomized complete block design, four blocks with four pigs each （one pig per treatment）. The trend of the response （linear or quadratic） was determined using orthogonal contrasts, and when a linear effect was determined, a linear equation was obtained. Results： The results showed that the inclusion up to 195 g/kg of CGF in the corn-soybean diet did not diminish the ileal digestibility （apparent and standardized） of protein and amino acids （P 〉 0.05）, except that of phenylalanine, cystine, and proline. A linear decrease （P 〈 0.05） per gram of CGF added to the diet in the apparent and standardized ileal digestibility of phenylalanine （0.011 and 0.015 percentage units, respectively）, cystine （0.048 and 0.043 percentage units, respectively）, and proline （0.045 and 0.047 percentage units, respectively） was noted. Similarly, ileal digestibility of dry matter and energy were adversely affected （reduced by 0.028 and 0.025 percentage units, respectively, per gram of CGF increment in the diet）. A significant （P 〈 0.05） linear reduction in total tract digestibility with increase in CGF amount in the diet was observed for energy （0.027 percentage units）, dry matter （0.027 percentage units）, crude protein （0.020 percentage units）, and neutral detergent fiber （0.041 percentage units） per gram of CGF added to the diet. Conclusion： CGF did not affect the ileal digestibility of protein and most amino acids but reduced the ileal and total tract digestibility of energy.

Effect of protease supplementation on apparent ileal crude protein and amino acid digestibility of over-processed soybean meals in broilers

Background: Nutritional value of proteins in feed ingredients can be negatively affected by hydrothermal processing, which causes large variation in the bioavailability of amino acids(AA) and negatively affects animal productive performance. Supplementation of exogenous proteases could increase the rate of digestion of damaged proteins, thereby increasing overall AA digestibility and bioavailability. The aim was to determine the effect of exogenous protease supplementation on the apparent ileal digestibility(AID) of crude protein(CP) and AA of soybean meals(SBM) with different degrees of hydrothermal processing in broilers.Methods: The experiment involved a 3 × 2 factorial arrangement, with SBM processing time(commercial SBM or autoclaved for 30 or 60 min at 120 ℃) and protease supplementation(not supplemented and supplemented) as factors. Protease was included at three times the recommended dose(0.06%) and the experimental diets were fed from 15 to 21 d.Results: The interaction between the effects of SBM processing and protease supplementation was significant for the AID of CP(P = 0.01), Trp(P = 0.01), Gly(P = 0.03) and Pro(P = 0.03), and also for the average daily gain(P = 0.01)and feed conversion ratio(P = 0.04). Increasing the processing time of SBM decreased(P < 0.0001) the AID of all amino acids, whilst the effect of protease supplementation was only significant for the AID of Phe(P = 0.02) and Tyr(P = 0.01).Conclusions: Exogenous protease supplementation at three times the commercial dose does not seem to offset the negative effects of hydrothermal processing of SBM on the apparent ileal digestibility of CP and amino acids or performance of broilers. Whilst positive numerical improvements of digestibility and performance(ADG and FCR)were noticed with protease supplementation at relatively mild processing levels, negative results were obtained with the harsh-processed meals.

Effects of the Standardized Ileal Digestible Lysine to Metabolizable Energy Ratio on Performance,Nutrient Digestibility,and Plasma Parameters of 10 to 28 kg Pigs

A total of 480 nursery pigs （Duroc x Landrace x Large White） were utilized in two experiments conducted to determine the effects of different ratios of standardized ileal digestible lysine （SID- Lys） to metabolizable energy （ME） ratio on the performance, nutrient digestibility, plasma urea nitrogen （PUN） ,and plasma free amino acids of 10 to 28 kg pigs. In Exp. 1, 192 pigs （ 10.58 kg） were assigned to one of four treatments. The treatments consisted of diets with a ME content of 3.2, 3.25, 3.3, or 3.35 Mcal/kg with a constant SID-Lys：ME ratio of 3.7 g/Mcal. The experiment lasted 28 days. Pigs which were fed the diets containing 3.3 and 3.35 Mcal/kg ME had lower feed intakes （ P 〈 0.05）than those fed 3.2 Mcal/kg. Feed efficiency was linearly improved with increasing dietary ME （ P 〈0.05）. Increasing the dietary ME level also increased （P 〈0.05 ） dry matter and energy digestibility. Therefore,3.3 Mcal/kg ME was selected for Exp. 2 in which 288 pigs （ 10.60 kg） were assigned to one of six treatments. Treatments consisted of SID-Lys： ME ratios of 3.1,3.3,3.5,3.7,3.9, or 4.1 g/Mcal with all diets providing 3.3 Mcal of ME/kg. Weight gain and feed efficiency were increased （P 〈0.05 ） as the SID-Lys：ME ratio in diet increased. Based on a straight broken-line model ,the estimated SID-Lys：ME ratio to maximize weight gain was 3.74.

Chemical composition,energy and amino acid digestibility in double-low rapeseed meal fed to growing pigs

Background： The nutritional value of rapeseed meal may be variable due to the variation of its chemical composition. And a precise understandin9 of the nutritional value of an ingredient is beneficial for the accurate diet formulation and reduction of feed costs. This study was conducted to determine the chemical composition, dicjestible energy （DE） and metabolizable enercjy （ME） content, and apparent ileal digestibility （AID） and standardized ileal dicjestibility （SID） of amino acids （AA） for growincj pigs. Thirteen solvent-extracted double-low rapeseed meal （DLIRSM） samples were obtained from the main double-low rapeseed producing areas in China. Methods： The DE and ME contents of the 13 DLRSM samples were measured in cjrowin9 pigs （six pigs per DLRSM sample, average initial body weicjht （BW） =48.3 kg）. The AID and SID of AA of 10 DLRSM samples were determined in 12 crossbred barrows （average initial BW = 35.3 kcj） by using two 6 x 6 Latin square designs. Each Latin square comprised one N-flee diet and 5 DLRSM test diets. Results： The chemical composition of DLRSM varied among samples, and the coefficient of variation was greater than ]0 % for ether extract （EE）, neutral detergent fiber （NDF）, acid detergent fiber （ADF）, calcium （Ca）, and total 91ucosinolates. The AA content of DLRSM varied among samples especially for lysine （Lys） and methionine （Met）. On a dry matter （DM） basis, the apparent total tract digestibility （ATFD） of gross energy （GE）, the DE and ME and the ME：DE ratio of DLRSM averaged 62.39 %, 2862 kcal/k9 and 2723 kcal/kcj, and 94.95 %, respectively. The mean value of S1D of Lys was 70.52 % which varied from 66.54-76.54 %. The SID of crude protein （CP）, Met, and threonine （Thr） averaged 72.81%, 82.41%, and 69.76 %, respectively. Conclusions： There was great variability in chemical composition especially in the concentration of EE, NDF and ADF, but no significant differences in energy content of the DLIRSM samples were observed. In addition, the AID and SID of all AA were relatively similar amoncj DLRSM samples except for that of Lys.

Estimation of endogenous protein and amino acid ileal losses in weaned piglets by regression analysis using diets with graded levels of casein

Background： Many studies have investigated endogenous loss of proteins and amino acids （AAs） at the ileal level in growing pigs. However, only a few studies have researched this subject in piglets. Knowledge regarding AA ileal digestibility in piglets would be helpful during the formulation of diets for weaning piglets, rather than just using coefficients obtained in growing pigs. Therefore, in this study, we sought to estimate endogenous protein and AA ileal losses in piglets. Furthermore, apparent and true ileal digestibility （AID and TID） of protein and AAs from casein were measured. Results： The average flow of protein was 20.8 g/kg of dry matter intake （DMI）. Basal protein loss, as estimated by regression, was 16.9 g/kg DMI. Glutamic acid, arginine, and aspartic acid （2.2, 1.4, and 1.2 g/kg DMI, respectively） were the AAs for which greater losses were seen. The AID of protein and AAs increased as the protein level in the diet increased. A higher increment in AID was observed between diets with 80 and160 g CP/kg of feed; this finding was mainly attributable to increases in glycine and arginine （46.1% and 18%, respectively）. The TID of protein was 97.8, and the TID of AAs varied from 93.9 for histidine to 100.2 for phenylalanine. Conclusions： The basal endogenous protein loss in piglets was 16.9 g/kg DMI. Endogenous protein was rich in glutamic acid, aspartic acid, and arginine, which represented 32.7% of endogenous protein loss in weaning piglets. The TID of casein was high and varied from 93.0 for histidine to 100.2 for phenylalanine.

Determination of the standardized ileal digestible calcium requirement of Ross broilers from hatch to day 14 post-hatch

An experiment was conducted to determine the standardized ileal digestible(SID)calcium requirement of fast-growing broilers from hatch to d 14 post-hatch.Ross 308(n=360)male broilers were obtained on day of hatch and allocated to 1 of 5 treatments in battery cages.There were 6 birds per cage and 12 pens per treatment.Four treatments were formulated to contain 0.60%,0.46%,0.32%or 0.18%SID Ca.The final treatment was formulated using total Ca to meet or exceed all nutrient requirements,including 0.90%total Ca and 0.49%non-phytate P(nPP),using the same ingredients.This treatment was the reference diet for comparison and validation of the SID Ca diets.Birds and feed were weighed at placement and on d 14.Tibias and ileal contents were obtained on d 14 and excreta was collected per pen and pooled on d 14.Data were analyzed using JMP Pro and requirements were estimated using 3different non-linear regression models.Increasing the SID Ca content in the diet from 0.18%to 0.60%improved(quadratic,P<0.05)body weight gain and mortality corrected feed conversion ratio(mFCR).The estimated SID Ca requirement to optimize gain or m FCR was between 0.39%and 0.52%.Tibia ash percent and weight increased(quadratic,P<0.05)as SID Ca content in the diet increased and the estimated SID Ca requirement was between 0.32%and 0.58%.Phosphorus utilization was improved in birds fed diets formulated using SID Ca compared with birds fed the reference diet.In conclusion,the SID Ca requirement of fast-growing broilers from hatch to d 14 was estimated between 0.534%and 0.398%when quadratic,straight-broken line,or quadratic-broken line regressions were used.These results agree with previously published data evaluating the SID Ca requirement of fast-growth broilers from hatch to d 10.

Prediction of protein and amino acid composition and digestibility in individual feedstuffs and mixed diets for pigs using near-infrared spectroscopy

Knowledge of the amounts and digestibility of amino acids in pig feedstuffs is essential for calculating the appropriate inclusion level in a complete diet.Wet chemical analysis and in vivo digestibility trials are time-consuming and costly and cannot be used for routine assessment.Near-infrared spectroscopy(NIRS)offers a rapid,cost effective and environmentally friendly method for evaluating feedstuffs.Calibrations models were developed using NIRS to predict the content of crude protein and 18 amino acids from a wide range of feedstuffs used in pig production(n=607).The samples ranged from single feed ingredients(containing amino acids from 0.3 to 129.8 g/kg of dry matter)to feed mixtures(containing amino acids from 1.2 to 53.2 g/kg of dry matter).The predictive ability of the calibrations was tested with an independent dataset(n=150)and with cross-validation.Furthermore,we compare these calibrations with calibrations developed on more narrowly defined groups of samples and with predictions from regression analysis of crude protein.The models were able to predict the concentrations of crude protein and 18 amino acids with good levels of precision and high coefficients of determination for calibration(RSQ^(CAL))from 0.91 to 0.99 and validation(RSQ^(VAL))from 0.87 to 0.97.Calibration models were able to predict all amino acids except tryptophan and valine with greater accuracy than those from protein regression.We also developed calibration models to predict the apparent ileal and total tract digestibility of protein and amino acids.With the exception of tryptophan,RSQ values(>0.7)and standard error of cross validation(SECV)values(<5%)were obtained for the digestibility of most of the amino acids.In conclusion,NIRS can be used to predict crude protein and amino acid concentrations from a wide range of single ingredients and feed mixtures used for pig diets without separate models for each feedstuff.The digestibility of protein and amino acids can be predicted with an acceptable accuracy to be useful in formulating pig diets.

Effects of dietary cellulose levels on the estimation of endogenous amino acid losses and amino acid digestibility for growing pigs

Two experiments were conducted to investigate the effects of dietary cellulose levels on the determination of the ileal endogenous losses(IEL) of amino acids(AA), apparent ileal digestibility(AID) and standardized ileal digestibility(SID) of AA in corn-soybean meal diets for growing pigs. In the first experiment, 28 pigs(BW, 45.1 ± 2.0 kg) that were fitted with simple T-cannulas at the distal ileum were fed 4 nitrogen-free diets consisting of 4 dietary cellulose levels(0, 3%, 6% and 9%) in a randomized complete block design. In the second experiment, 28 pigs(BW, 45.6 ± 2.0 kg) fitted with simple Tcannulas at the distal ileum were fed 4 corn-soybean meal diets consisting of 4 dietary cellulose levels(0,3%, 6% and 9%) in a randomized complete block design. There were 7 replicates per diet with 1 pig as a replicate in each treatment. Both experiments consisted of a 7-d adjustment period and a 2-d ileal digesta collection period on d 8 and 9. Chromic oxide was used as an indigestible marker to calculate IEL and digestibility of AA. The results showed that the IEL of AA for growing pigs was not influenced by dietary cellulose supplementation(P > 0.05). The AID of Thr, Ser, Glu, Cys, Ile, Tyr, Phe, Lys and His decreased with increasing cellulose supplementation levels for pigs fed corn-soybean meal diets(P < 0.05). The SID of Thr, Ser, Cys, Val, Ile, Tyr, Phe, Lys and His decreased with increasing cellulose supplementation levels in corn-soybean meal diets(P < 0.05). In summary, dietary cellulose levels had no effect on the estimation of IEL of AA for growing pigs. The AID and SID of most AA in corn-soybean meal diets decreased with increasing levels of dietary cellulose supplementation.