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Subject: Animal Science × End date: 2009 × Start date: 2004 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Study of different regimen of total and digestible amino acids based diets on broilers
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2008-05) Maghsoudlou, Shahriar; Ashok Kumar
    This research was exerted to study the effects of feed replacement from starter to grower and grower to finisher diets on performance and nitrogen excretion of broilers at different growth periods with diets formulated based on total and digestible amino acids, to select the proper feed formulation strategy and feeding program for broiler production considering biological and economic performances and minimum excretion of nitrogenous compounds into the environment. The experiment was conducted in a 3×2×2 factorial experiment with 3 replicates of 12 broiler chickens of either sex allotted for each treatment (total 36 floor pens) and 432 Cobb Vantress broiler chickens in a completely randomized design. A corn-soybean control diet with high amino acid digestibility (HD) was compared to another diet using rice bran and meat meal to partially replace corn and soybean meal, this second diet with low amino acid digestibility (LD), was formulated to contain the same levels of total lysine and total sulfur amino acids as per HD diet. A third diet (LD+AA) was similar to LD diet but formulated to obtain levels of true ileal digestible amino acids equal to HD diet. Different regimens of these three diets were obtained by changing times of starter to grower diets (at 7 and 21 days) and grower to finisher diets (at 28 days and without finisher) Birds consumed a grower diet for varying times depending upon termination of starter diets and initiation of finisher diets. All dietary treatments were evaluated on the basis of biological, economic and nitrogenous excretion traits at different periods. The result of this study showed that there was a significant (p<0.05) interaction effect between diet types (types of feed formulation) and changing time of starter to grower diet on biological traits (feed, metabolizable energy and nutrients intake and their conversion into body weight gain), economic traits (feed cost per bird and monetary return per bird) and excretion of nitrogenous compounds (total nitrogen and uric acid as the percentage of excreta) by the chicks. Increase in time of starter diets resulted in better performance and less nitrogen excretion when diets were formulated based on digestible amino acids and decrease in time of starter diet resulted in higher production and less nitrogen excretion, when diets were formulated based on total amino acid composition of feed ingredients. Changing time of grower to finisher diets had no significant (p>0.05) effect on biological, economic performances of broilers. It may imply that a two-stage phase feeding (starter and grower) resulted in almost similar performance with three-stage phase feeding (starter, grower and finisher). The results of this study also showed that feed formulation based on digestible amino acid may have more benefit in earlier ages or at the time of feeding starter diet where the crude protein concentration of diet is high. At this period, formulation based on digestible amino acids resulted in better performance and less nitrogen excretion into the environment. However, in later ages, this effect was not significant (p>0.05). Other results obtained by this study showed that generally programs supporting biological performance could also support monetary returns however, these programs may not necessarily support minimum excretion of nitrogenous compounds into environment or even they may result in higher excretion of nitrogen excretion into the environment. At shorter growth period of 0-28 d, regimens were superior in biological and economic performances resulted in less nitrogen and uric acid excretion into the excreta. However, at longer growth period of 0-42 d, generally regimens were superior in biological performance resulted in higher nitrogenous compound excretion into the excreta. In this case, using criterions of economic performance and environmental health (instead of biological performance and environmental health) may result in more number of regimens achieving these goals.