Influence of sunflower meal based diets supplemented with exogenous enzyme and digestible lysine on performance, digestibility and carcass response of broiler chickens

Response of broiler chickens to 2 levels of endo-1,4-β xylanase (EC 3.2.1.8) and endo-1,3-β glucanase (EC 3.2.1.6) cocktail (with and without), 3 levels of digestible lysine (8.0, 9.0 and 10.0 g kg−1 with the applicability of ideal protein concept), and 2 levels of sunflower meal (SFM; 200 and 300 g kg−1) were evaluated in the present experiment. The factorial design of 2 × 3 × 2 using 2448 one-day-old straight-run Hubbard broiler chicks was used to evaluate the effect of two levels of enzymes, 3 levels of digestible lysine and 2 levels of SFM in practical vegetable based mash diets having 11.51 MJ ME and 190 g CP kg−1 from 1 to 42 d of age. The BW gain was improved linearly (P≤0.001) with the increasing level of digestible lysine during 1–21 d and 22–42 d of age. The gain:feed was improved linearly (P≤0.001) with the increasing digestible lysine during 1–21 d and a quadratic effect of digestible lysine was noted during 1–42 d where 9.0 and 10.0 g digestible lysine kg−1 of diet responded similar for gain:feed. Enzyme supplementation at 300 g SFM kg−1 improved BW gain (P≤0.008) and gain:feed (P≤0.048) during 1–21 d. When 10.0 g digestible lysine kg−1 of diet was used at 2 levels of SFM, gain:feed was improved (P≤0.013) during 1–21 d. However, this interaction was not significant on other performance parameters either at 21 d or at 42 d of age. The enzyme supplementation decreased the feed intake (P≤0.019) by 4.67% and improved gain:feed by 5.53% (P≤0.012) during 1–42 d without affecting BW gain. The main effect of SFM was not significant for live performance or carcass response at any stage. The depression in breast weights at 42 d due to 300 g SFM or 8.0 g digestible lysine kg−1 of diet was compensated by the enzyme addition (a significant enzyme × SFM effect). No significant effect of enzyme, SFM, digestible lysine or their interactions was observed on apparent metabolizable energy of the diets. Coefficient of total tract apparent digestibility of nitrogen was improved by the addition of enzyme to 10.0 g digestible lysine kg−1 of diet or addition of digestible lysine to high SFM. The results of the present study revealed a positive response of enzyme addition in low nutrient density and high SFM diets. Moreover, digestible lysine is not suggested to be lowered than 10.0 g during 1–21 d and it may be reduced to 9.0 g kg−1 if a single diet having high level of SFM is planned to be offered during 1–42 d.