Comparative study of apparent metabolizable energy and net energy values of dephenolized cottonseed proteins for laying hens

Optimizing the energy utilization of nutrients and ensuring maximum benefits are continuous goals for livestock producers.The net energy(NE)value of feed reflects its nutritional value in the precision feeding system.An experiment was conducted to determine the apparent metabolizable energy(AME)and NE values of 3 types of dephenolized cottonseed protein(DCP)for Hy Line Brown hens aged 42 to 45 weeks using the reference diet substitution method.A reference diet based on corn soybean meal was used to meet the nutritional needs of Hy Line Brown laying hens.To render the crude protein and energy values of the 3 test diets similar,10.5%,12%,and 16%of the gross energy yielding ingredients from the reference diet were replaced with DCP 1,DCP 2,and DCP 3,respectively.The birds were fed 4 diets during a 7-d adaptation period.After the dietary adaptation period,2 birds per replicate from each treatment group were placed in an individual open circuit respiratory calorimetry chamber for a 3-d experimental period.Daily O_(2)consumption and CO_(2)production were recorded,and excreta samples were collected.The AME values of DCP 1,DCP 2,and DCP 3 were 3,049.05,2,820.13,and 2,982.31 kcal/kg of dry matter(DM),respectively.The NE values of DCP 1,DCP 2,DCP 3 were 1,475.77,1,910.31,and 1,905.37 kcal/kg of DM,respectively,and the NE:AME ratios were 48.40%,67.74%,and 63.89%,respectively.Our data show that the AME value of DCP does not reflect the nutritional value of the feed.The NE value of DCP with a high ME value was not necessarily high.

Net energy,energy utilization,and nitrogen and energy balance affected by dietary pea supplementation in broilers

Pea starch consists predominantly of C-type of amylopectin chain which is more resistant to digestive enzymes than A-type of starch thus slowly digested in poultry.It was hypothesized that the presence of slowly digested pea starch in broiler diets will increase net energy and the efficiency of energy utilization in broilers.Two experiments were performed to investigate starch digestibility of pea at different in-cubation times(in vitro study)and the effect of dietary pea on heat increment and net energy in broilers using an open-circuit respiratory calorimetry system(in vivo study).One-day-old Ross 308 male broilers were fed a common starter crumble from d 1 to 10 and standard grower diets thereafter.At d 21,birds were transferred to the chambers each housing 2 birds.Each treatment was replicated 6 times with 2 identical runs of 3 replicates per treatment.A wheat-soybean meal-based diet was used as a control and the treatment diet contained 500 g of pea/kg pea.In vitro study showed that pellet processing increased(P<0.001)starch digestibility,particularly at shorter times for wheat and a much larger response for pea.Birds offered the pea-based diet had lower(P=0.002)feed intake,lower(P=0.020)body weight gain,but a similar(P>0.05)FCR compared to those offered the wheat-based diet.Net energy(NE)and apparent metabolizable energy(AME)values were higher in the pea-based diet than in the wheat-based diet(P-0.037 for NE and P-0.018 for AME).Heat production,respiratory quotient,heat increment of feed,efficiency of utilization of gross energy for AME,and efficiency of utilization of AME for NE did not differ(P>0.05)between the 2 treatments.There was no effect(P>0.05)of pea on the total tract di-gestibilities of dry matter,crude protein and ash,but the total tract digestibility of starch was higher(P-0.022)in the pea-based diet compared to the wheat-based diet.This study provides insight into the energy metabolism of broilers offered a pea-based diet and indicates that dietary pea supplementation increases dietary AME and NE but has no effect on heat increment of feed and the efficiency of energy utilization in broilers.