Multiprotease improves amino acid release in vitro, energy, and nutrient utilization in broilers fed diets varying in crude protein levels.

Low crude protein (CP) diets can reduce nitrogen (N) excretion and costs by increasing N utilization efficiency. Exogenous proteases may further improve protein digestibility in low CP diets. This study first evaluated in vitro the efficacy of a multiprotease on amino acid (AA) release from feedstuffs and broiler feed. Later, a broiler study evaluated the effect of feeding corn-soybean meal diets containing 3 CP levels (17, 19, and 21% CP) with supplementation on top of 0 or 2,400 U/kg multiprotease on chicken growth performance, total tract CP, and ileal AA digestibilities, and energy utilization. Ross 708 male chickens were placed in 42 cages and assigned to 6 treatments resulting from a 3 × 2 factorial arrangement. Three isocaloric basal diets were formulated to reduce CP, but all diets maintained digestible Lys:CP in 5.47% and the same ideal protein profile. Data were analyzed in a completely randomized design. On average, the multiprotease increased (P < 0.05) in vitro free AA release by 27.81% in most feedstuffs evaluated compared to the control. For broiler feed, 1,200 U/g multiprotease addition improved (P < 0.001) in vitro free AA release by 18.90%. This multiprotease showed interaction effects (P < 0.05) on chicken FCR, energy, and CP digestibility. As expected, BW at 24 d, BW gain, and FCR (8-24 d) worsened (P < 0.001) as dietary CP reduced from 21 to 17%, and multiprotease addition did not improve (P > 0.05) these parameters. BW gain decreased by 12.9% when N intake was reduced from 49.32 to 38.49 g/bird. Multiprotease supplementation improved (P < 0.01) AMEn by 71 kcal/kg, CP digestibility from 59.45 to 63.51%, ileal AA digestibility, and DM digestibility from 67.08 to 73.49%, but only in the 21% CP diet. No differences in ileal AA digestibility due to CP level (P > 0.05) were detected, except for Cys digestibility (P < 0.01). In conclusion, low CP diets reduced growth performance and improved N utilization but negatively affected energy utilization efficiency. Exogenous multiprotease supplementation improved AME, AMEn, protein, ileal AA, and DM digestibility in the 21% CP diet without significantly affecting growth performance.

Effects of oregano (Lippia origanoides) essential oil supplementation on the performance, egg quality, and intestinal morphometry of Isa Brown laying hens.

BACKGROUND AND AIM: The use of antibiotics as growth promoters in the feed of poultry, has contributed to an increase in the antimicrobial resistance of foodborne pathogens worldwide. Hence, the development of new effective alternatives to antibiotics that do not hinder productivity is imperative. For this, the aim of the present study was to determine whether oregano essential oil (OEO) extracted from Lippia origanoides is a suitable alternative to growth-promoting antibiotics (GPAs) for improving the performance, egg quality, and intestinal morphometry of ISA Brown laying hens. MATERIALS AND METHODS: A total of ninety-six 70-week-old ISA Brown laying hens were randomly assigned to four treatment groups with four replicates per treatment and six hens per replicate. The treatments consisted of four different diets that were formulated according to the nutritional requirements of the genetic line and the production phase with and without the addition of GPA and OEO: NC, which did not contain OEO or GPA; GPA, which included 50 ppm zinc bacitracin as a GPA; 80OEO, which included 80 ppm OEO and no GPA; and 150OEO, which included 150 ppm OEO and no GPA. RESULTS: All of the OEO and GPA treatment groups had a better feed conversion ratio than the NC group. However, the addition of 150 ppm OEO to the diet improved the percentage egg production and egg mass, as well as the external and internal quality of the egg compared with the other treatments. In addition, both the 80OEO and 150OEO treatments improved the yolk color, shell thickness, and shell color, as well as parameters related to the intestinal morphometry compared with the NC group. CONCLUSION: The findings of this study indicate that 150 ppm OEO can be used as a substitute for GPA to improve the performance, egg quality, and parameters related to the intestinal morphometry of ISA Brown laying hens.