Utilization of chitosan extracted from shrimp waste meal as a prebiotic for broilers

Janbandhu, A.V., Ravi, A., Ramana, J.V. and Narendranath, D. 2020. Utilization of chitosan extracted from shrimp waste meal as a prebiotic for broilers. Animal Nutrition and Feed Technology, 20: 477–490. The objective of the study was to extract chitosan from shrimp waste meal by a bioremediation method using organic acids along with yeast and to evaluate the prebiotic effect of the extracted chitosan in commercial broilers. The optimum concentration of the acids and time of incubation was initially studied by incubating the shrimp waste meal with 1, 4 and 8 per cent HCl or 5, 10 and 20 per cent organic acids (namely, fumaric, propionic and lactic acids) for 24, 48 and 72 h and based on the pH change, demineralization and deproteinization of shrimp waste meal. Subsequently, 8% HCl and 20% organic acids were used for the extraction of the chitosan for evaluation in broiler diets. The extracted chitosan was characterized by FT-IR. Commercial broiler chicks (n=360) were allotted to five groups (T1 to T5) with four replicates per treatment and each replicate containing 18 birds. While T1 served as the control group with no chitosan, the diets for groups T2, T3, T4 and T5 additionally contained 1% chitosan (as a prebiotic) extracted using 8% HCl, 20% fumaric acid, 20% lactic acid and 20% propionic acid, respectively. The growth trial was carried out for 6 weeks. The overall BW gain and FCR was improved in birds under the chitosan-supplemented groups T2 to T5 than the control (T1) birds. There was a significant (P<0.01) reduction in Eschorihia coli and Salmonella counts in caecal contents, increase in the villi length (VL) of duodenum, jejunum and ileum, reduction in crypt depth (CD) and increase in the VL:CD ratio in the treatment groups of birds (T2 to T5) than in T1 group of birds. It is concluded that 20% organic acids along with yeast were effective as an alternative to the chemical method for extracting chitosan from shrimp waste meal as revealed by the characteristics and prebiotic effect of the extracted chitosan in commercial broilers.