Estimated phosphorous requirement with and without added phytase of starting broiler chicks

For poultry the availability of phosphorus from ingredients of plant origin is limited, because this element is bound to phytates, and birds do not produce the enzyme phytase. Thus, it is necessary to complement their diets with inorganic P. Recently, microbial phytase has been utilized to improve the availability of P from phytates. Two experiments were conducted to calculate the optimal biological level of available P (Pa) with and without phytase, and to evaluate the effect of phytase on body weight gain (WG) and ash content of the tibia (% ASH) of broilers from 1-21 days of age. In Expt. 1 seven levels of Pa were evaluate: 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, and 0.60%; in Expt. 2, four levels of Pa 0.15, 0.27, 0.39, and 0.51%, and four levels of phytase 0, 200, 400, and 600 FTU (units of phytase/kg of diet) were evaluated in a factorial arrangement. In Expt. 1 there were differences (P<.05) in WG and % ASH with the levels of 0.45 and 0.50% Pa being the best. The optimal biological level was 0.46% for WG, similar to the 0.45% proposed by NRC (1994); and 0.49% for%ASH. In Exp. 2 the effect of phytase level onWGand%ASH, followed a linear tendency, the 600 FTU level surpassing the 0 FTU level by 13.5% forWGand 8.5 for%ASH (P<.05). The optimal biological level (P<.05) of Pa forWGwas estimated as 0.47 with 0 FTU and 0.394% with 600 FTU, and for%ASH as 0.47% with 0 FTU and 0.43% with 600 FTU. For maximum WG it is possible to reduce the inorganic P level by 0.75 g/kg diet (0.075%) when supplementing with 600 FTU)

Duration of heat treatment and true digestibility of amino acids in meat meal for Leghorn cockerels

Knowledge of the true digestibility of amino acids in the ingredients of a poultry ration is important in order to use them properly, especially the proteinic ingredients that have been heated during processing, such as meat meal. Protein solubility is a good indicator of heat damage. To estimate true digestibility, Leghorn White cockerels were fasted for 24 h and then force fed with meat meal autoclaved at 121°C and 1.5 kg/cm2 for 0, 15, 30, 45 and 60 minutes. A correction for endogenous amino acids was included. Nitrogen was determined by micro Kjeldahl; protein solubility by the methods of 2% KOH and coomassie blue; amino acids concentrations were also determined by HPLC. Treatments had an effect (P<.05) on meat meal protein solubility, means being 89% and 84% for the KOH and coomassie blue methods, respectively. However, protein solubility increased until 30 minutes and then decreased according to the KOH method, whereas it increased until 15 minutes (P<.05) and then remained constant by the coomassie blue method. Autoclaving had an effect on true digestibility of all amino acids, except methionine. There was a high and significant correlation (0.81) between protein solubility by the KOH method and true digestibility of amino acids

Estimation of metabolizable energy and utilization of fly larvae (Musca domestica L.) in the feeding of broilers

Larvae of the domestic fly (Musca domestica L.) seem to be a viable alternative for use in animal feeding. Thus, in this study the appparent and true metabolic energy contents, corrected for nitrogen balance, of dry larvae, were estimated by the method of Sibbald, as 4 071 ± 133 and 4 252 ± 218 kcal kg-1, respectively. For evaluation of dry fly larvae as a protein and energy source for broilers, an experiment of 7 weeks duration was conducted, using 70 female day-old chicks of the Ross strain, divided into five experimental units of 7 chicks each assigned to each of two treatments. The experimental design was completely randomized with repeated measurements. All chicks were housed in wire floor, electrically heated batteries until 4 weeks of age, and then moved to grower batteries. The treatments were: T1, diet with dry fly larvae; and T2, diet with soybean meal and soybean oil; both diets in mash form and supplemented with sorghum, minerals, and vitamins, were offered ad libtium. Experimental data were recorded weekly. No differences (P>.05) were found between T1 and T2 in bodyweight gain (2 107 vs 2 148 g), feed intake (4 064 vs 4 158g), and in feed conversion ratio (1.93 vs 1.94), respectively. Three birds on each treatment died from ascites syndrome. The results show that the protein and energy supplied by the dry fly larvae support animal performance similar to that of chicks fed a conventional diet of sorghum-soybean