Effects of Feeding Sunflower Meal and Superdosing Phytase on the Production Traits and Nutrient Digestion of Broiler Chickens

Sunflower meal (SFM) is an alternative protein source for poultry. It is locally available and cheap, and its protein is rich in methionine and cystine. The high fibre and phytate content of SFM are, however, limitation factors. The aim of this study was to examine the effects of feeding SFM and using superdosing phytase (1500 FTU) on the production performance and nutrient digestibility of broiler chickens. A total of 576-day-old male Ross 308 broilers were fed four iso-nitrogenous and iso-caloric diets: control (C), C with superdosing phytase (CP), SFM, and SFM with superdosing phytase (SFMP). SFM was included at 20% and 30% in the grower and finisher phases, respectively. Neither SFM nor phytase superdosing affected the production traits in the grower phase. However, in the finisher phase, SFM significantly increased body weight gain (BWG) and decreased the feed conversion ratio (FCR). This positive result was also true for the cumulative performance of birds. On day 42, feeding SFM increased fat digestibility and the AMEn content of diets, but decreased the digestion of starch. Superdosing phytase increased both fat and starch digestion, as well as the AMEn and the N-retention of chickens. SFM was found to have no effect on the apparent ileal amino acid (AA) digestibility. Conversely, the phytase treatment significantly increased the absorption of several essential AAs. In conclusion, not only is fibre SFM tolerated by broiler chickens, but it can also improve production traits. Although superdosing phytase positively affects the digestibility of nutrients, it fails to cause changes in the BWG or FCR of chickens.