RESUMEN
This study aimed to evaluate the effect of supplementing different protease enzymes on growth performance, intestinal morphology, and selected carcass traits in broilers fed diets reduced 3.5% in crude protein (CP) and amino acids (AA). One thousand one-day-old Ross 308 broilers (41 g) were assigned to five dietary treatments with ten replicates of 20 birds each: a positive control (PC) diet formulated to meet Ross 308 AA requirements, a negative control (NC) diet reformulated to provide 3.5% lower CP and AA compared to PC, NC supplemented with a multi-protease (PR1) solution, containing 3 different coated proteases produced from Aspergillus niger, Bacillus subtilis and Bacillus licheniformis, NC supplemented with a serine protease (PR2) produced from Bacillus licheniformis, and NC supplemented with an alkaline protease (PR3) produced from Bacillus licheniformis. At slaughter, 40 birds per treatment were used to assess the effect of the different treatments on carcass traits. At 32 days, samples of the duodenum, jejunum, and ileum of 10 birds per treatment were collected for intestinal morphology evaluation. Birds fed PC and NC supplemented with multi-protease exhibited better (p < 0.05) feed efficiency compared to NC and NC supplemented with all the other protease enzymes. Multi-protease supplementation was linked to the highest (p < 0.05) carcass weight and yield. There were significant differences (p < 0.05) between treatments in all gut segments, with PC, PR1, PR2, and PR3 exhibiting longer villi height (VH) compared to NC. This study demonstrates that 3.5% reduction of CP and AA negatively affected for the overall period feed efficiency, carcass yield, and intestinal morphology. The supplementation of the multi-protease restored feed efficiency and improved carcass yield.
RESUMEN
Carcass parameters and meat quality in lambs that consumed diets having layer hen litter (LL) were evaluated in a complete randomized study. Forty-two lambs were allocated equally (14 lambs/treatment diet) into one of three iso-nitrogenous diets for 75 days. To partially replace soybean meal and barley, LL was given at 0 (LL0), 150 (LL150), or 300 g/kg (LL300) of dietary dry matter (DM). At the termination of the trial, the characteristics of carcasses (hot and cold carcass weight, dressing percentage, and carcass cuts) and meat quality (Musculus longissimus linear dimensions, ultimate pH, cooking loss, water holding capacity (WHC), shear force (SF), color coordinates) were measured after slaughtering all lambs. Longissimus muscle weight was greatest (p < 0.05) for the LL150. For the dissected loin, intermuscular fat content was lowest for the LL0 diet. However, subcutaneous fat content was lower (p < 0.05) in the LL300 diet than LL0 and LL150 diets. Rib fat depth and Musculus longissimus area were greater (p < 0.05) for LL150 than L0. No differences were found in meat pH or color parameters among treatments but WHC and SF were lower in L0 lambs than in lambs fed LL containing diets. Cooking loss was greater for the LL300 diet than the LL0 diet. In summary, quality of meat and carcasses data indicate the possibility of inclusion of LL up to 300 g/kg DM to growing Awassi lambs.
RESUMEN
Twenty nursing Awassi ewes (BW = 50 ± 2.35 kg, age = 4.5 ± 1.2 years) with their lambs were used to evaluate the effects of feeding calcium salts in lactation diets on performance and pre-weaning growth of their lambs. Treatments were 0% calcium salts (CON) or 5% calcium salts (FAT). At the end of the study, a digestibility experiment was performed. Milk yield was greater (P < 0.05) for ewes fed the FAT diet than the CON diet. Milk composition was similar (P > 0.05) between diets. However, milk energy value (kcal/day) tended to be greater (P = 0.07) for the FAT diet than the CON diet. Concentrations of milk C18:1c9 and C20:0 were greater (P < 0.05) in ewes fed the FAT diet than the CON diet. However, concentration of trans-10, cis-12 CLA was lower (P = 0.05) in the FAT diet than in the CON diet. No differences in feed intake and body weight change were detected between diets. Digestibility of dry matter, organic matter, crude protein, ether extract, neutral detergent fiber, and acid detergent fiber were similar (P > 0.05) for diets. For lambs, weaning weight was not affected by treatments. However, average daily gain and total gain were greater (P = 0.053) for the FAT diet than the CON diet. Results suggest that supplementing lactating ewes with calcium salts at the beginning of lactation phase improves daily milk yield of ewes and pre-weaning growth of their lambs with no major negative impact on feed intake and digestibility.