| Silver fox is one of the precious fur animals.High percentage of animal source protein in their diet is necessary to obtain high quality pelt.Fish meal is widely used in Chinese feed production,however,increasing price of this protein feed draw many interests to find alternatives to fish meal.Soy bean meal is a valuable plant protein source but its application is limited in silver fox diet due to multiple anti-nutritional factors contained in soybean meal.Various studies have shown that fermented soy bean meal prepared with engineering microbes is beneficial to livestock and poultry.There is no report in literature about the use of fermented soy bean meal in silver fox.In this thesis,the fermented soybean meal was added to the silver fox diet to study the effect of the supplementation on the digestibility,growth and pelt quality of the silver fox,and to provide a theoretical basis for the feasibility of replacing fish meal with fermented soybean meal.One hundred and twenty weaned silver foxes with similar body weight were randomly divided into 4 groups(C,T1,T2 and T3),with 30 animals in each group.Animals were fed a basal diet(C)and basal diet supplemented with 5,10,and 20% fermented soy bean meal to replace corresponding amount of soy bean meal and partial fish(T1,T2 and T3)to form four isonitrogenours diets,respectively.The experiment last 120 days,during which time the experimental animal were weighed 3 times,feeding trials were conducted during growth and fur growing periods and pelts quality was assessed.During growth(August)and fur growing(October)periods,six animals(half male and half female.)were selected from each group to conduct two feeding trials.There was an at least two weeks of preliminary feeding periods for each trial.Total fecal collection method was applied to measured dietary nutrient digestion.Pellet feed was used in growing and powder feed was used in fur growing periods.Tree days and 5 days samples collection time were applied to compare the dry matter digestibility between the two sampling times to determine the minimum sampling duration without affecting on the precision of the results.The results showed that the difference in dry matter digestibility of silver foxes among groups was not significant(P>0.05).There was no significant difference in crude protein digestibility among the silver foxes fed the powder diet(P>0.05).When feeding pellets,the crude protein digestibility for the control group was significantly lower than that for the experimental groups(P<0.01).C<T1<T3<T2.There was no significant difference in the digestibility of organic matter between treatments(P>0.05).Dry matter digestibilities determined with 3 and 5 days total fecal collection did not differ significantly and closely related(R=0.97),indicating that sampling time con be as short as 3 days.At the beginning of the experiment(at the end of July),at the end of the growth period(at the end of September)and before the slaughter(at the end of November),each animal was weighed on an empty stomach and the weight gain during the growing period and the winter hairy period was measured.The result is as follows:There was no significant difference in weight gain and average daily weight gain of silver fox among treatments during the growth period and fur growing periods(P>0.05).After the winter hair matures,the experimental animal were slaughtered and pelts were took off.After drying,the pelts length,dry pelt weight,guard hair length,down length,and pelt grade are measured.The results showed that there was no significant difference in pelt length,dry pelt weight,and down length among treatments(P>0.05).The percentage of grade I pelts(85cm-95cm)in group C and T1 was higher than that in the other two groups.The proportion of grade II pelts(80cm-85cm)was the highest in the T1 group.The proportion of grade III pelts(75cm-80cm)was highest in the T3 group. |
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