Nutritional Evaluation Of Cottonseed Meal On Digestible Energy,metabolizable Energy And Amino Acid Digestibility In Sows

This study aimed to evaluate the nutritional value of cottonseed meal(CSM)from different regions of Xinjiang,China,on gestating and non-pregnant sows.The study analyzed the chemical composition of six types of CSM and determined their digestible and metabolic energy values,prediction equations,and standard ileal digestibility of crude protein and amino acids(AAs)for both gestating and non-pregnant sows.Exp.1;Analyzed composition of the six CSM.Six representative CSM samples were collected from processing plants in Xinjiang,China for chemical composition analysis.Results showed that the gross energy(GE)was similar among the six samples,but the coefficients of variation exceeded 10%for crude fiber(CF),neutral detergent fiber(NDF),acid detergent fiber(ADF),crude protein(CP),some minerals,vitamins,and free gossypol(FG).The range of CP content is 40.67%～59.63%.Arginine was the most abundant indispensable AA and ranged from 4.73%to 7.78%.Glutamic acid was the most abundant dispensable AA and ranged from 7.89%to 13.0%.With the increase of CF,NDF and ADF,CP decreased,and the highest content of FG was also found in CSM(1077.75mg/kg,as fed basis).Exp.2;Nutritional evaluation of CSM on digestible energy and metabolizableenergy and in sows.Fourteen gestating sows(parity three;220.6±18.4 kg at d 35 of gestation)and 14non-pregnant sows(parity three;219±14.6 kg after the lactation period)were assigned to a replicated 7×3 Youden square design with 7 diets and 3 periods.The 7 diets included a corn-based diet and 6 diets containing 20.00%CSM.Both gestating sows and non-pregnant sows were fed 3.0 kg/d of the respective experimental diets.In each period,after 5 d acclimation to the experimental diets,urine and feces were collected for 5 d.Results indicated that non-pregnant sows had greater apparent total tract digestibility(ATTD)of organic matter(OM)and CP(P<0.01)compared with gestating sows.The digestible energy(DE)and metabolizable energy(ME)values of the six CSM samples ranged from 12.48 to 17.15 MJ/kg and 11.35 to 15.88 MJ/kg when fed to non-pregnant sows,from 12.86 to 16.41 MJ/kg and12.43 to 14.72 MJ/kg when fed to gestating sows(on a dry matter basis).However,the DE,ME values and ME:DE ratio were observed no difference when fed to gestating and non-pregnant sows.The best prediction equations of DE and ME of CSM in gestating sows are DE[MJ/kg DM]=18.27–0.17×NDF(R~2=0.98)and ME[MJ/kg DM]=1.29×DE+0.82(R~2=0.94),respectively.The best prediction equations of DE and ME of CSM in non-pregnant sows are DE[MJ/kg DM]=17.33–0.26×ADF(R~2=0.96)and ME[MJ/kg DM]=0.89×DE+0.46(R~2=0.94),respectively.Exp.3;Nutritional evaluation of CSM on amino acid digestibility in sows.Post-weaning sows(Landrace×Yorkshire;LY)that have finished three parities were fitted with T-cannula in the distal ileum,a total of 7 gestating sows(LY,4th parity,35 days of pregnancy,239.4±11.0kg)and 14 non-pregnant sows(LY,3-5 parity,245.0±14.2 kg)entered the experiment.The gestating sows were allotted to a 7×6 Latin square experimental design,and the experimental diet was based on corn starch,including one nitrogen-free diet and six cottonseed meal diets.Each diet treatment had six replicates,and each replicate had one sow.The non-pregnant sows were allotted to a replicated 7×3 incomplete Latin square design with 7 diets and 3 periods,respectively.Two replicates were included in each period resulting in a total of 6 replicates per treatment.Each period covered a 5-d acclimation of diets and a 2-d sample collection period on the 6th and 7th day.Diets included a cornstarch-based nitrogen-free(NF)diet to calculate endogenous losses of protein and AAs and 6 CSM diets which were cornstarch-based diets containing 32%CSM as the only source of AAs.All experimental sows were fed 3.0 kg/d of the respective experimental diets,and all diets contained 0.3%chromium trioxide.Results indicated that the apparent ileal digestibility(AID)of CP was significantly affected by diets for both gestating and non-pregnant sows.The AID of CP in CSM 1(75.58%)was significantly lower than in CSM 4(80.42%),CSM 5(80.50%),and CSM 6(82.44%)diets for gestating sows.The AID of CP in CSM 1(77.88%)was significantly lower than in the CSM 6(81.87%)diets for non-pregnant sows(P<0.05).The SID of CP was significantly affected by diets for both gestating(P<0.01)and non-pregnant sows(P=0.06).For gestating sows,the AID of indispensable AA ranged from 63.90%(tryptophan)to 91.38%(arginine).For non-pregnant sows,the AID of indispensable AA ranged from 46.31%(proline)to 92.11%(arginine).For gestating sows,the indispensable AA Cysteine,Glycine,Proline,and Tyrosine had significantly different standard ileal digestibility(SID)between different groups(P<0.05).For non-pregnant sows,The SID of Arginine,Lysine,Methionine,Threonine,Aspartic acid,Cysteine,and Serine had different values among different diets(P<0.05).Conclusions:1.The DE and ME values of the CSM samples in the present study averaged 14.52 MJ/kg and 13.19 MJ/kg,respectively,for non-pregnant sows,and 14.40MJ/kg and 13.24 MJ/kg,respectively,for gestating sows.In general,DE and ME were positively associated with CP content,but negatively associated with fiber content.2.The SID of AA in sows can be greater affected by the fiber and free gossypol content,the cottonseeds processed with solvent extraction can have a greater ileal digestibility of AA.