Comparative Digestibility Of Energy In Common Feed Ingredients To Barrows At Different Body Weights

Five experiments were conducted to determine the digestible energy(DE)and metabolizable energy(ME)and apparent total tract digestibility(ATTD)of gross energy(GE)and other chemical nutrients in different ingredients fed to barrows and to quantify the effect of body weight(BW)on the digestibility of the ingredients.Finally,there was a study about validation of the metabolizable energy of corn DDGS and wheat bran in growing pigs and finishing pigs.In Exp.1,three diets were fed to 108 kg finished pigs at a feeding level close to their ad libitum intake and to nonlactating,nonpregnant(240 kg)sows slightly above their maintenance energy level(2.4 kg/d).The main objectives of this study were to compare the total tract digestibility of dietary energy or nutrients of the three diets in finished pigs and adult sows and to analyze the effect of diet chemical composition on total tract digestibility in both groups of pigs.The results show that the total tract digestibility of energy or nutrients was higher(P<0.05)in adult sows than in finished pigs;the total tract digestibility which suggests that the origin of the difference between the two physiological stages is mainly due to a higher rate of degradation of dietary fiber in the hindgut of sows.In Exp.2,the study was conducted to determine the DE and ME and apparent total tract digestibility(ATTD)of gross energy(GE)and other chemical constituents in 4 cereal grains(corn,wheat,barley and sorghum)fed to barrows and to quantify the effect of body weight(BW:13 kg,31 kg,57 kg,and 111 kg)on the digestibility of the 4 cereal grains.The daily DMI,GE intake and GE loss in faeces and urine increased as pig BW increased(P<0.05).DE,ME and the ATTD of GE and crude protein(CP)for pigs fed corn and wheat were greater than for pigs fed barley and sorghum(P<0.05).Overall,DE and ME values and ATTD of GE and CP were greater for pigs fed corn and wheat than barley and sorghum and the digestive abiity of pigs fed any of the cereal grains was improved with increased live weight of pigs.Therefore,differences in the digestible energy content of different cereal grains for pigs of different BW indicate that the effective energy values of various ingredients for pigs at different physiological stages should be considered in order to accurately and economically formulate diets based on these cereal grains.In Exp.3,the objective of the study was to determine the digestible(DE)and metabolizable energy(ME)density and the coefficient of apparent total tract digestibility(CATTD)of gross energy(GE)in 5 protein sources(soybean meal,cottonseed meal,rapeseed meal,corn gluten meal,and maize distillers dried grains with solubles(DDGS)and a control(corn substituted for protein source)fed to barrows and to quantify the effect of physiological stage(29 kg,58 kg,and 105 kg)on the digestibility of the 5 protein ingredients.Both DE and ME of corn gluten meal were greater(P<0.05)compared to the other ingredients for barrows at all physiological stages.Soybean meal had greater(P<0.05)DE than corn,maize DDGS,rapeseed meal and cottonseed meal,and greater(P<0.05)ME than cottonseed meal,rapeseed meal and maize DDGS at each physiological stage.The CATTD of both GE and OM in corn gluten meal,soybean meal and corn were greater(P<0.05)than that in maize DDGS,rapeseed meal and cottonseed meal for barrows at all physiological stages.In stage 3,barrows had greater(P<0.05)CATTD of GE and OM compared to those at stages 1 and 2 when corn,cottonseed meal or maize DDGS were fed.In conclusion,there are differences in the DE and ME content when different protein ingredients are fed to pigs at different physiological stages.In Exp.4,the study was conducted to determine the digestible energy(DE)and metabolizable energy(ME)values and coefficient of apparent total tract digestibility(CATTD)of gross energy(GE)in four fiber ingredients(corn distillers dried grains with solubles(corn DDGS),soybean hull,wheat bran,and corn bran)fed to barrows,and to quantify the effect of growth stage(29 kg,59 kg,and 106 kg)on digestibility of these four fiber ingredients.Corn DDGS diet had greater DE and ME values compared with diets containing other three fiber ingredients,regardless of the growth stage(P<0.05).Corn bran diet showed lower CATTD of GE,OM and NDF compared with diets containing other three fiber ingredients at all growth stage(P<0.05).Soybean hull diet had the lowest CATTD of CP among the four fiber diets at all growth stage(P<0.05).Corn DDGS and soybean hull diets had greater CATTD of ADF compared with wheat bran and corn bran diets at all growth stage(P<0.05).Digestibility of energy and nutrients of the four fiber ingredients showed the same pattern as their diets.The body weight(BW)also had effects on energy and nutrients digestibility of the four fiber ingredients and their diets.In conclusion,four fiber ingredients corn DDGS,soybean hull,wheat bran and corn bran had different DE and ME values as well as energy and nutrient digestibility for barrows at different growth stage(with different BWs).In Exp.5,there was a study about validation of the metabolizable energy of corn DDGS and wheat bran in growing pigs(27 kg)and finished pigs(103 kg).The results showed that there was no significant difference in F/G among treatments at the same level of dietary ME.Our study indicates that energy values of ingredients for pigs at different growth stage should be considered to improve the accuracy of diet formulation.