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34th Annual Australian Poultry Science Symposium
The following technical article is related to the event::
34th Annual Australian Poultry Science Symposium

Response of Broilers to Dietary Inclusions of Sugarcane Bagasse and Protease in a Reduced Crude Protein Diet

Published on: 1/10/2023
Author/s : N.K. SHARMA 1, S. K. KHERAVII 1, K. GURNEY 2, M. CHOCT 1 and S.-B. WU 1 / 1 School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia; 2 Redsun Nutrition Pty Ltd, Munruben QLD 4125, Australia.
Nutritional strategies to improve performance of broilers offered reduced crude protein (RCP) diets supplemented with crystalline amino acids are of interest to the poultry industry. We hypothesized that the dietary inclusion of moderate amounts of insoluble fibre would stimulate gizzard function and increase the retention time of digesta in the foregut allowing more time for exogenous protease to act on their substrates leading to greater digestibility of protein/amino acids and better performance of birds offered RCP diets. This study investigated the effectiveness of dietary sugarcane bagasse as an insoluble fibre source with or without an exogenous protease in RCP diets fed to broilers.
A total of 672 d-old Ross 308 male parent-line birds were fed a common starter diet until 10 d of age. On d 10, birds were assigned to 8 treatments, each replicated 6 times with 14 birds per pen in a 2 × 2 × 2 factorial arrangement of treatments with dietary crude protein (CP)- normal (NCP, 213 g/kg CP for 10 to 24 d in grower phase and 195 g/kg CP for 24 to 35 d in finisher phase) or reduced by 25 g/kg CP in both the grower and finisher phases, bagasse included in the diets at 0 or 20 g/kg and protease added over the top of the diets at 0 or 0.2 g/kg. The diets were cold-pelleted and contained wheat, sorghum and soybean meal as major ingredients. All diets were supplemented with xylanase and phytase and were formulated to meet Ross 308 nutrient specifications. Feed intake, weight gain, and FCR were determined from d 10 to 35. Carcass parameters were measured on d 35 and 42. JMP Pro 14 was used to perform analyses of variance and significance was determined at P < 0.05 using Tukey’s HSD test.
The reduction in dietary CP decreased feed intake (P < 0.001) by 3.66% (3361 versus 3238 g), weight gain (P < 0.001) by 5.78% (2284 versus 2152 g) and increased FCR (P < 0.001) by 3.2 points (1.476 versus 1.508) during d 10 to 35. Protease or bagasse had no effect (P > 0.05) on feed intake during the experimental periods. A 3-way CP × bagasse × protease interaction was observed for weight gain during d 10 to 24 (P < 0.05) and for FCR during d 10 to 24 and d 10 to 35 (P < 0.01). During d 10 to 24, weight gain was increased by 4.37% (1030 versus 1075 g) when protease was added to the NCP diet without bagasse but not when it was added to the RCP diet without bagasse. Meanwhile, FCR was decreased by protease in all except when bagasse was added to the NCP diet. On the other hand, dietary inclusion of bagasse only reduced FCR when no protease was added in the NCP diet (1.354 versus 1.327 during d 10 to 24 and 1.476 versus 1.459 during d 10 to 35) but not in any other circumstance. There were no further improvements in weight gain and FCR when bagasse and protease were added in tandem in the NCP diet. Bagasse increased (P < 0.01) relative gizzard weight by 8.47% on d 35 and 9.52% on d 42. Reduction in CP decreased (P < 0.01) relative pancreas weight by 14.01% and tended to decrease (P = 0.057) breast meat yield (181 versus 176 g/kg) on d 42. A 3-way CP × bagasse × protease interaction (P < 0.01) was observed for the relative abdominal fat pad weight on d 42. The relative abdominal fat pad weight decreased when protease or bagasse alone was added to the NCP diet but increased when added to the RCP diet (P < 0.01). No changes were observed when they were added in tandem.
This study showed that dietary supplementation of bagasse or protease alone improved performance of broilers offered a NCP diet. There were no further improvements on performance when they were added in tandem. The addition of protease alone in the RCP diet improved FCR. The RCP diet in this study may have been marginal in some other amino acids, possibly glycine which led to the lack of response of bagasse addition in the RCP treatment.
ACKNOWLEDGEMENTS: This research was funded by the AgriFutures Australia.
        
Presented at the 32th Annual Australian Poultry Science Symposium 2021. For information on the next edition, click here.
 
Author/s :
Mingan is the Chief Executive Officer of the Poultry Cooperative Research Centre and a professor at the University of New England. Mingan's main areas of interest include carbohydrate chemistry and nutrition, feed enzymes, energy evaluation and nutrition x disease interaction in poultry. He has supervised more than 40 postgraduate students and published over 270 papers in journals and proceedings. He is an active member of the scientific community, serving as assistant editor and on editorial boards of many journals.
 
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