This study evaluated the effects of dietary fat levels on the growth, nutrient digestibility, nitrogen balance and pelt characteristics of the blue fox(Alopex lagopus). Age-matched blue foxes(12 weeks old) with simila...This study evaluated the effects of dietary fat levels on the growth, nutrient digestibility, nitrogen balance and pelt characteristics of the blue fox(Alopex lagopus). Age-matched blue foxes(12 weeks old) with similar body weights were randomly divided into six dietary groups over 98 days, during the growing-furring period. Blue foxes in the six groups were fed with experimental diets containing 10%(groupⅠ), 12%(groupⅡ), 14%(group Ⅲ), 16%(group Ⅳ), 18%(groupⅤ) and 20%(group Ⅵ) fat during the growing period(from 13 weeks to 18 weeks of age);foxes were fed with diets containing 12%(groupⅠ), 14%(groupⅡ), 16%(group Ⅲ), 18%(group Ⅳ), 20%(groupⅤ) and 22%(group Ⅵ) fat during the furring period(from 18 weeks to 26 weeks of age). The results indicated that 16%-18% dietary fat, during the growing period significantly improved nutrient utilization, and as a main energy source, significantly reduced the feed/gain ratio. A dietary fat level of 18%, during the furring period not only improved the growth and development and decreased the feed/gain ratio, but also increased nutrient digestibility and fur quality. These data, combined with data from a conic regression model, showed that dietary fat levels between 16.29% and 18.40%, during the growing period and between 17.72% and 18.72%, during the furring period enhanced the growth performance and fur quality of blue foxes.展开更多
The purpose of this experiment was to isolate and screen the microorganisms from the soil where chicken feathers were piled for a long time and identify them biologically.Single-factor test and response surface method...The purpose of this experiment was to isolate and screen the microorganisms from the soil where chicken feathers were piled for a long time and identify them biologically.Single-factor test and response surface methodology(RSM)analyses were used to explore the optimum conditions for the growth and fermentation of a strain.Screening of bacterial strains from the soil where feathers were piled for a long time was performed,and 12 keratinolytic bacterial strains were isolated.One of these isolates,CH-7,was found to be the most effective feather-degrading strain,which was identified as Lactococcus lactis KU568489.1.The growth situation of feather keratin degrading bacterium analysis results showed that the best degradation effect of CH-7 was found in oxygen,inoculation 5%,initial pH=6.5,fermentation temperature 30℃,speed 220 r·min-1 and fermentation time 36 h,and CH-7 had the highest degradation rate of feather keratin.The optimization analysis of RSM showed that there was more significances of the three factors,32℃,pH 6.3 and amount of inoculum at 5.7%on the degradation of feather keratin.Based on the above results,the feather degrading bacterium,Lactococcus lactis CH-7,was obtained by screening,30℃and pH 5.5-6.5 were the best growth conditions.The oxygen,the amount of inoculum 5.7%,the fermentation temperature,32℃,pH 6.3 and the rotational speed 220 r·min-1 were the best fermentation conditions.Under these conditions,38.48%degradation rate was obtained after 36 h fermentation,which demonstrated the strain CH-7 was potential to the fermented feather meal for feed.展开更多
基金Supported by the Harbin Applied Technology Research and Development Project(2016RAXXJ015)
文摘This study evaluated the effects of dietary fat levels on the growth, nutrient digestibility, nitrogen balance and pelt characteristics of the blue fox(Alopex lagopus). Age-matched blue foxes(12 weeks old) with similar body weights were randomly divided into six dietary groups over 98 days, during the growing-furring period. Blue foxes in the six groups were fed with experimental diets containing 10%(groupⅠ), 12%(groupⅡ), 14%(group Ⅲ), 16%(group Ⅳ), 18%(groupⅤ) and 20%(group Ⅵ) fat during the growing period(from 13 weeks to 18 weeks of age);foxes were fed with diets containing 12%(groupⅠ), 14%(groupⅡ), 16%(group Ⅲ), 18%(group Ⅳ), 20%(groupⅤ) and 22%(group Ⅵ) fat during the furring period(from 18 weeks to 26 weeks of age). The results indicated that 16%-18% dietary fat, during the growing period significantly improved nutrient utilization, and as a main energy source, significantly reduced the feed/gain ratio. A dietary fat level of 18%, during the furring period not only improved the growth and development and decreased the feed/gain ratio, but also increased nutrient digestibility and fur quality. These data, combined with data from a conic regression model, showed that dietary fat levels between 16.29% and 18.40%, during the growing period and between 17.72% and 18.72%, during the furring period enhanced the growth performance and fur quality of blue foxes.
基金Supported by Harbin Applied Technology Research and Development Project(2016RAXXJ015)。
文摘The purpose of this experiment was to isolate and screen the microorganisms from the soil where chicken feathers were piled for a long time and identify them biologically.Single-factor test and response surface methodology(RSM)analyses were used to explore the optimum conditions for the growth and fermentation of a strain.Screening of bacterial strains from the soil where feathers were piled for a long time was performed,and 12 keratinolytic bacterial strains were isolated.One of these isolates,CH-7,was found to be the most effective feather-degrading strain,which was identified as Lactococcus lactis KU568489.1.The growth situation of feather keratin degrading bacterium analysis results showed that the best degradation effect of CH-7 was found in oxygen,inoculation 5%,initial pH=6.5,fermentation temperature 30℃,speed 220 r·min-1 and fermentation time 36 h,and CH-7 had the highest degradation rate of feather keratin.The optimization analysis of RSM showed that there was more significances of the three factors,32℃,pH 6.3 and amount of inoculum at 5.7%on the degradation of feather keratin.Based on the above results,the feather degrading bacterium,Lactococcus lactis CH-7,was obtained by screening,30℃and pH 5.5-6.5 were the best growth conditions.The oxygen,the amount of inoculum 5.7%,the fermentation temperature,32℃,pH 6.3 and the rotational speed 220 r·min-1 were the best fermentation conditions.Under these conditions,38.48%degradation rate was obtained after 36 h fermentation,which demonstrated the strain CH-7 was potential to the fermented feather meal for feed.
