نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه علوم دامی، دانشکده کشاورزی، دانشگاه بیرجند
2 گروه علوم دامی، دانشکده کشاورزی، دانشگاه بیرجند، بیرجند، ایران
3 گروه علوم دامی، دانشگاه بیرجند، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and objectives: Dense poultry production systems, especially broiler chickens, generate significant amounts of manure that can be utilized as feed for ruminants. However, the production of ammonia, methane, and hydrogen sulfide, along with the spread of pathogenic microorganisms, are major environmental concerns in this field. Therefore, the purpose of this study is to investigate the effects of different thermal processing methods on microbial populations and the metabolic properties of poultry broiler litter (PBL) protein, as well as their impacts on nutrient digestibility and blood metabolites in pregnant ewes.
Materials and methods: PBL was treated using four methods: 1) moist heat at 121°C for 15 minutes (1.5 atmospheres) (HPT), 2) dry heat at 150°C for 20 min (HT150), 3) dry heat at 80°C for 40 min (HT80), and 4) dry heat at 60°C for 24 h (HT60). The total microbial count, as well as the populations of coliforms, fungi and mold, and the pathogens Salmonella and Escherichia coli, were determined using the method recommended by the Food Safety and Inspection Service. Additionally, the DVE/OEB protein evaluation system was used to determine the protein metabolic properties. Next, 96 pregnant ewes (Kurdish × Baluchi mixed) were divided into 4 groups of 24 each in a completely randomized design. PBL processing was carried out in high volume using the selected processing method. The ewes were fed diets containing four levels of treated PBL: 0%, 8%, 16%, and 24%. The experimental period lasted for 6 weeks before lambing and 3 weeks after lambing, during which the effects of the experimental treatments on reproductive characteristics, nutrient digestibility, and some blood metabolites were investigated.
Results: All thermal processing methods resulted in a reduction of the total microbial count compared to the raw PBL. Using HT150 inactivated Salmonella and Escherichia coli and completely removed coliforms. The average fungus and mold populations were similar in the raw and 80°C and 60°C treated PBL (P>0.05). The 60°C processed PBL increased OEB (-17 vs. -15 g/kg) and DVBE (13 vs. 10 g/kg) compared to the raw PBL (P<0.05). The substitution of 24% processed poultry litter resulted in a 20.67% decrease in pregnancy retention and a 19.86% decrease in lamb birth weight compared to the control group (P<0.05). Furthermore, feeding ewes with 16% processed poultry litter did not significantly alter the apparent digestibility of dry matter, organic matter, and crude protein during the pre-partum and post-partum periods (P>0.05). However, 24% treated PBL increased blood glucose in the prepartum period (68.81 vs. 63.07 mg/dL, P<0.05) but not postpartum (P>0.05). Blood urea nitrogen and cholesterol concentrations linearly increased with higher processed litter levels in both periods (P<0.05).
Conclusion: Enhancements in the CP metabolic properties were observed across all PBL processing methods. The HT150 method was superior to HPT due to microbial inactivation and pathogen elimination (Salmonella and Escherichia coli) while requiring less equipment and cost. Feeding pregnant ewes 8% treated PBL in the pre- partum period and 16% in the post- partum period, without compromising the DM, OM, and CP digestibility, can help reduce dietary costs without adverse effects.
کلیدواژهها [English]
)