Diet Composition and Using Probiotics or Symbiotics Can Modify the Urinary and Faecal Nitrogen Ratio of Broiler Chicken's Excreta and Also the Dynamics of In Vitro Ammonia Emission

Ammonia emission is a main air quality issue worldwide and related mostly to animal production. This ratio in the European Union is about 80-90%. Ammonia is released from the manure, mainly from the nitrogen excreted via urine. There are several nutritional tools to decrease the N-excretion of the animals. Among them feeding low protein diets supplemented with crystalline ammino acids is probably the most efficient. However, feed additives, like exogenous enzymes, pro- and prebiotics can also modify the amount of the excreted N as well as its composition. There are lots of information on how the probiotics and prebiotics can modify the microbiota composition in the different gut segments. On the other hand, few results exist on how this modified microbiota can affect the ratio of the faecal and urinary nitrogen or the ureolytic activity of the excreted microflora. Therefore, in the present work the effects of different cereal grains with different soluble fibre fractions and a probiotic and symbiotic treatment was evaluated. The objective of this research was to determine whether diet composition, or adding probiotic or symbiotic feed additives to broiler diets can modify the N composition of the excreta and the dynamics of ammonia volatilization from the manure. A total of 574 one-day-old Ross 308 broiler chickens were fed four different diets. The treatments included a corn and soybean meal-based control diets (C), wheat-based and wheat bran containing diets (W), a multi-strain probiotic treatment (Broilact((R)); Br), and a symbiotic additive containing Bacillus subtilis, inulin, and Saccharomices cerevisiae (Sy). Feeding the wheat-based diet significantly improved the weight gain and FCR of chickens. Treatment W also significantly increased the dry matter content of the excreta compared with the probiotic and symbiotic treatments. Both Br and Sy tended to decrease the amount of excreted uric acid, which is the main substrate of ammonia. Treatment Sy reduced the urinary N ratio of the excreta in comparison with treatment W. The symbiotic additive resulted in significantly higher ammonia emission in the first two hours. On the other hand, the dynamics of the emission was slow at the beginning and increased steeply after 15 h when the wheat-based diets were fed. Based on our results, the wheat-based diets, containing soluble arabinoxylans, and the symbiotic treatments of broiler diets have an impact on the urinary and faecal nitrogen composition of the excreta, and also on the dynamics of ammonia release from the manure.

Automated summary

Ammonia emission is a significant air quality issue worldwide, mainly related to animal production, with the European Union accounting for about 80-90%. The release of ammonia from manure is primarily due to nitrogen excreted through urine. There are various nutritional methods to decrease nitrogen excretion, such as feeding low protein diets supplemented with crystalline amino acids. Feed additives, including exogenous enzymes, pro- and prebiotics, can also modify nitrogen excretion and composition. However, there is limited information on how modified microbiota affects nitrogen ratio and ureolytic activity. This study evaluated the effects of different cereal grains, soluble fiber fractions, and probiotic and symbiotic treatments on ammonia release and nitrogen composition in broiler excreta.