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Reduced dietary crude protein as a strategy for sustainable egg production

Jayaraman, B., F. Poernama, T. Wibowo, P. Krishnan and G. Channarayapatna

A study was conducted to determine the effects of feeding reduced crude protein-amino acid (CP-AA) balanced diets on production performance and egg quality of commercial laying hens. A total of 960 Lohmann Brown laying hens were randomly allocated into three dietary treatments (10 replicates per treatment, 32 birds per replicate). Dietary treatments consisted of three different CP levels, high CP (17.5%; High CP), medium CP (16.2%; Med CP), and low CP (15.2%; Low CP) diets. In High CP diet, only DL-Methionine (Met) and L-Lysine (Lys) were supplemented. In Med CP diet, in addition to Met and Lys, threonine (Thr) and trypto- phan (Trp) were also supplemented. In Low CP diet, besides Met, Lys, Thr, and Trp, L-Valine and L-Isoleucine were supplemented. Corn-soy- bean meal-based diets were formulated to meet nutrient requirements ac- cording to Lohmann breed standards for the laying phase and provided in mash form. The total duration of the study was 16 weeks (24 weeks to 40 weeks). Feed and water were provided ad libitum throughout the experi- mental period. Response criteria measured were hen-day egg production (HDEP), feed intake, egg mass, feed conversion ratio (FCR) and Haugh unit score (HUS). Data were analyzed as one-way ANOVA using SAS software version 9.4. Mean values were compared by Tukey’s test and statistical significance was declared at P < 0.05. Performance parameters like HDEP and feed intake were unaffected (P > 0.05) when dietary CP was reduced from 17.5% to 15.2%. Reduction of dietary CP from 17.5% to 16.2% did not affect FCR and egg mass; however extreme reduction of CP negatively impacted the above performance parameters. HUS as an indicator of egg equality was unaffected (P > 0.05) by the dietary CP levels. The income over feed cost (IOFC) for the Lohmann-Brown laying hens fed Med CP diet was the highest followed by high CP diet and low CP diet. Low CP diet could also be a sustainable solution when next limiting AA are commercially available at cost-effective price.

In conclusion, the results from this study indicate that dietary CP reduction could be an effective nutritional strategy to improve sustainability of the egg industry.