Effects of Conditioning Methods on the Physical and Microbiological Quality of Broiler Pelleted Feeds

Background: The physical and hygienic quality of pelleted feed can be affected by various factors, including temperature and retention time during the conditioning process.Objectives: This study aimed to compare the effects of producing pellets with conventional and super-conditioner methods at various temperatures and retention times on pellet quality in term of microbial and physical parameters and the recovery rate of phytase. Methods: Eight broiler diets were prepared, including mash feed, conventional pellets (COP), and ۶ super-conditioner pellets (SUP), processed at ۷۰ °C, ۸۰ °C, and ۹۰ °C for ۳ and ۶ minutes. The total counts of aerobic bacteria and fungi, the pellet durability index (PDI), hardness, and the recovery rate of the included phytase were then compared among the treatments.Results: Compared to the mash feed, the total number of viable bacteria in the COP and SUP treatments decreased as the temperature and retention times increased. The fungal population was significantly lower in the pellet treatments than in the mash feed; furthermore, the SUP treatments exhibited a lower fungal count than the COP treatment. The PDI were higher (P≤۰.۰۵) in the SUP۸۰ and SUP۹۰ treatments than in the COP and SUP۷۰ treatments. Pellet hardness was also higher (P≤۰.۰۵) in the SUP۹۰ treatments than the other pellet treatments. However, phytase activity in the pelleted feeds significantly decreased compared with the mash feed. Conclusion: The results indicate that an increase in the conditioner temperature may improve feed quality parameters; a conditioner temperature of ۸۰ °C is recommended for optimal broiler chicken pellet production when using the super-conditioner method.

کلیدواژه ها:

hardness ، pelleted feed ، pellet durability index ، Phytase ، super conditioner