Evaluation of a multicarbohydrase and phytase complex in reduced energy, amino acids, available phosphorus and calcium diets fed to broilers

Abstract

The aim of this study was to determine the nutritional potential of a multicarbohydrase and phytase complex (MCPC) through its effect on growth performance, carcass traits and bone characteristics in chickens fed wheat-corn soybean meal-based diets reduced in metabolizable energy (ME), digestible amino acids (dig. AA), available phosphorus (avP) and total calcium (Ca). A total of 3150-day-old Ross 308 chicks were fed a common starter diet formulated to meet the nutritional requirements of birds from 1 to 10 days of age and were then randomly assigned to 7 dietary treatments with 15 pens of 30 birds per pen replicate. Treatments consisted of a nutrient adequate-positive control (PC) diet and 3 negative control (NC1, NC2, NC3) diets similarly reduced in avP and Ca by 0.18 and 0.16% unit, respectively, but differently reduced in dig. AA (3.0, 4.5, and 6.0%), and in ME (93 kcal, 124 kcal, and 155 kcal per kg diet) with and without MCPC (1,250 xylanase U, 860 β-glucanase U and 1,000 FTU/kg phytase diet). Body weight (BW) and feed intake (FI) were measured at 10, 28, and 42 days of age, and body weight gain (BW gain) and feed conversion ratio (FCR) were calculated for each period. At 42 days of age, 4 birds per pen replicate were randomly chosen for carcass traits determination. In addition, 1 bird per pen replicate was randomly chosen for tibia breaking strength and mineralization. Compared with PC diet, the energy and nutrient reductions negatively affected the overall BW gain and FCR (P < 0.0001) without a significant reduction of FI (P = 0.18). The largest nutrient decrease, NC3-fed birds exhibited higher FCR (+2.5%, P < 0.05) than birds fed NC1, whilst there was no significant difference between birds fed the different NC diets on BW gain and FI. The addition of MCPC to NC diets restored the overall (10–42 d) BWG (P = 0.44) and FCR (P = 0.84) to the same levels as the PC diet suggesting a nutritional potential of the enzyme solution as far as the NC3 nutrient decrease. The reduction of ME and nutrients also reduced (P < 0.01) the carcass traits, breast, and leg weights. Tibia breaking strength and ash, Ca and P contents were negatively affected (P < 0.01) in energy and nutrient-deficient diets. These carcass and tibia traits were also restored by MCPC supplementation to NC diets and became similar as those with the PC diet (P > 0.08). This study showed that MCPC supplementation could compensate up to 6% dig. AA and 155 kcal ME/kg reduction as well as 0.18% and 0.16% units of avP and total Ca allowing to save feed cost while guaranteeing the same performances.