PSXVI-22 Protease for laying hens as a strategy to save on feed cost and reduce nitrogen excretion.

Abstract

Performance of laying hens is influenced by age. With age their nutritional needs change and egg quality tends to decrease. Protease supplementation offers opportunity to reduce crude protein (CP) and amino acid (AA) levels in diets generating savings on feed cost and reducing nitrogen (N) excretion in the environment. This study was conducted to determine the effects of reducing CP and AA in diets supplemented or not with protease on performance and N excretion of aged laying hens. A 6 weeks study was conducted using 240 Hy-Line Brown hens 82-week-old randomly allotted in 120 cages with 8 replications of 5 cages (2 hens/cage) fed one of the following three treatments: 1) PC (Positive Control, 17% CP), 2) NC (Negative Control, -11% CP and AA), 3) PT (NC + 125 ppm Protease, Jefo, Canada). Data were subjected to statistical analyses of variance (PROC Mixed procedure, SAS). LSMEANS with PDIFF option was used to separate treatments means (P<0.05). Difference in CP and AA between PC and NC treatments was voluntarily set higher than the recommended uplift for the protease tested in order to generate substantial drop on performance. Compared to PC, reducing CP and AA in NC diet impaired performance of laying hens. The effect was numerical on feed conversion ratio (P<0.11, +6.8%), observed as a trend on egg mass (P<0.10, -7.4%) and significant on egg weight (P<0.05, -2.7%). Protease supplementation counteracted the negative effects of reduced CP and AA, recovering +1.2% on egg weight (P<0.05), +4.5% on egg mass (P<0.10) and -4.0% on feed conversion ratio (P=0.11). Nitrogen output was lowered (P<0.01) in NC and PT compared to PC. Overall, results showed that protease supplementation on low protein diets and aged layers can successfully be used as a strategy to save on feed costs and lower N excretion in the environment.