Effect of genotype and diet on growth performances of broiler chickens and environmental parameters

The effects of two different dietary protein sources, pea bean (Pisum sativum L.; P) vs soybean (Glicine max L.; S), were investigated on in vivo performances of two genotypes broiler chickens and on environmental impact. A total of 120 male birds 20-day-old, 60 Kabir Rosso Plus (KP) and 60 New Red (NR), were randomly divided into four homogeneous groups (P-KP, S-KP, P-NR, S-NR) housed in 20 floor pens (n=6). From d 47 to d 83 of age, each group was fed an average of 1.18 kg dry matter (DM)/group including a mixture of wheat bran, durum wheat, corn meal and faba bean, mixed either to soybean (3.39%) in S group, or to pea bean (6.78%) in P group. Diets were isoenergetic and isonitrogenous. Birds had free access to water during the trial. Group DM intake was daily recorded. At d 36 of the trial, group body weight (BW) was recorded, and both group average daily gain (ADG) and feed conversion rate (FCR) were calculated. Data on DM intake, BW, ADG and FCR were processed by ANOVA, in a 2×2 factorial design. Greenhouse gas (GHG) emissions were evaluated in one-year period by Global Livestock Environmental Assessment Model – Interactive (GLEAM-i, ver. 1.8). Diet did not affect (P>0.05) group DM intake, BW, ADG and FCR. Compared to KP, NR showed higher group DM intake (P<0.001) and BW (P<0.01) while ADG and FCR (P>0.05) were similar between the two genotypes. Regarding the global warming potential, P diet was found less impactful, showing -7.0% of total GHG emissions and -24.1% of total CO2 than S diet. Taken together results suggest that pea bean can successfully substitute soybean in broiler chicken diet so that the dietary substitution could represent a possible management strategy to reach a trade-off between good farming practices and environmental protection on small scale.