The Growth Performance, Nutrient Digestibility, Gut Bacteria and Bone Strength of Broilers Offered Alternative, Sustainable Diets Varying in Nutrient Specification and Phytase Dose

Abstract

This study assessed the use of locally sourced sustainable feed ingredients, rapeseed meal (RSM) and maize dried distiller grains with solubles (DDGS) in diets over traditional ingredients on the growth performance, bone strength and nutrient digestibility of broilers. This work also investigated the effects of supplementing exogenous phytase in two doses (500 vs. 1500 FTU/kg). Using male Ross 308 chicks (n = 320) assigned to receive one of four experimental diets: (1) Positive control diet 1 (PC1), a wheat, soya-based diet + 500 FTU/kg phytase. (2) Positive control diet 2, RSM/DDGS diet + 500 FTU/kg phytase (PC2). (3) Negative control (NC) reduced nutrient RSM/DDGS diet, no phytase. (4) The NC diet plus 1500 FTU/kg phytase (NC+). PC1 birds displayed higher feed intake and body weight gain consistently throughout the trial (p < 0.001) as well as increased body weight by 28 d and 42 d (p < 0.001). Whole-body dual emission X-ray absorptiometry (DXA) analysis revealed PC1 birds also had higher bone mineral density (BMD), bone mineral content (BMC), total bone mass, total lean mass and total fat mass than birds offered other treatments (p < 0.01). Diet had no significant effect on bone strength. Phytase superdosing improved the digestibility of dry matter (DM), neutral detergent fibre (NDF), gross energy (GE), calcium (Ca), potassium (K) and magnesium (Mg) compared to birds in other treatment groups. The phytase superdose also improved performance in comparison to birds offered the NC diet. Phytase superdosing increased the IP6 and IP5 degradation and increased the ileal inositol concentration of the birds. N excretion was lower for birds offered the traditional wheat–soya diet and highest for those offered the high-specification RSM/DDGS diet with a commercial dose of phytase. The addition of a phytase superdose to the negative control diet (NC+) reduced P excretion of birds by 15% compared to birds offered NC.

Effect of Bacterial Phytase on Growth Performance, Nutrient Utilization, and Bone Mineralization in Broilers Fed Pelleted Diets

“…Phytase inclusion decreased excreta P concentration by approximately 27%, which could be, to a major extent, attributed to the releasing effect of phytase enzyme on PAbound P, and it leads us toward more environmentally sustainable broiler production. Similar to current results, Mulvenna et al [48] reported a 20% reduction during 0-28 d on a g/kg BW gain basis and a reduction of 15% in total P excretion to 2.2 kg target weight in broilers fed phytase-supplemented diets.…”

Impact of Zymomonas Mobilis Treated Corn Cobs on Growth Performance, Apparent Nutrient Digestibility, Ileal Digesta Viscosity and Cost Benefits of Broiler Chickens

“…This might be attributed to the potential role of Zymomonas mobilis making more nutrients available for growth. This was in agreement with the observation of Mulvenna et al (2022) who reported that a traditional soya-based diet with commercial exogenous phytase resulted in the best growth response in broiler chickens. However, this report was contrary to the observation of Biesek et al (2020) who reported that broiler finishers fed legume seeds and rape seed meal have significantly reduced body weight gain and increased feed conversion ratio in the experimental groups than the control group fed soyabean meal based diet.…”

“…This agreed with the reports of Hartinger et al (2022), who reported higher body weight, average daily gain and improved feed conversion ratio when Hermetia illucens defatted larvae meal-based diets were fed to Ross 308 broiler chickens as a protein source. Several similar reports have been observed in earlier studies (Janocha et al, 2022 andMulvenna et al, 2022). The reduced feed intake in broiler chickens fed 100 % CCZ could indicate the adequacy of the energy content of the diet because birds feed to satisfy their energy need.…”

Weighted single-step GWAS identified candidate genes associated with carcass traits in a Chinese yellow-feathered chicken population

“…Bone formation (GO:0060349) encompasses the intricate processes of growth, differentiation, and tissue development in bones, which is meticulously regulated by pivotal factors including bone morphogenetic proteins ( BMPs ), the Wnt signaling pathway, and parathyroid hormone-related peptide ( PTHrP ) ( Li et al, 2009 ). Notably, Mulvenna et al (2022) have demonstrated that manipulating the nutritional specifications and phytase enzyme dosage in broiler chicken feed can exert a discernible impact on the robustness of their skeletal structure. A comprehensive comprehension of the underlying molecular mechanisms governing avian bone formation is essential for investigating skeletal disorders, elucidating bone growth regulation, and enhancing poultry production.…”