Study On The Effects And Mechanismof Papaya Powder On Growth And Lactation Of Rabbit

In the study, effects of papaya powder on growth, reproductivity, development of digestive organs, immunity and nutrient digestibility of New Zealand white rabbit were comprehensively investigated. The optimal dosage of papaya powder feeded to rabbit was defined and the mechanism of papaya powder function on rabbit was also explained in the study. This will be beneficial to the development of new feed additives, from plant material and to the non-pollution and efficient breeding of rabbit, and further to widen application of pawpaw in livestock industryIn Experment 1, effect of papaya powder on growth of New Zealand white rabbit was investigated. Ninety six 35-day-old healthy rabbits were randomly divided into four groups (groupⅠ,Ⅱ,Ⅲand control),24 rabbits per group.2%,5%,8%and none papaya powder were respectively added in the rations of groupⅠ,Ⅱ,Ⅲand control rabbits. Results showed that 5%or 8%pawpaw powder is beneficial to growth of the rabbits. Average weight gain per day in groupⅠ,ⅡandⅢrabbits was 8.4%(P<0.05), 20.5%(P<0.01) and 18.0%(P<0.01) higher than that of the control. And there are significant difference between groupⅡ(or groupⅢ) and groupⅠ(P<0.01). No difference was found between groupⅡandⅢ. Rabbit intake of groups fed with papaya powder was obviously higher than that of the control (P<0.05), but feed conversion ratio didn't show difference within the four groups (P>0.05). So, feed added with papaya powder was beneficial to improve intake and growth of the rabbits but didn't have effect on feed conversion ratio. Effect of papaya powder on immunity of New Zealand white rabbit was also investigated with biochemical and serological assays. Results showed that number of diarrhea and death in the test groups of rabbits was lower than those of the control. Rabbit mortality rates for groupⅠ,ⅡandⅢwere 4.2,12.5 and 8.3 lower than that of the control respectively. Contents of Serum cholesterol of the test-groups rabbits were 146.0%(P<0.01),21.8%(P>0.05) and 73.9% (P<0.05) higher than that of control. The average total protein of groupⅡrabbits was 60.81±2.51g/L, highest among the four groups. The average total protein of group III and the control was close each other, but both obviously higher than that of group I (P<0.05). The average level of albumin in-group II is 36.00±0.47g/L, higher than other groups. There was no difference between other groups. Changes of serum globulin showed same trend with total protein. Levels of IgG, IgA and IgM didn't show difference among the four groups (P>0.05)In Experiment 2, effect of papaya powder on nutrient digestibility of New Zealand white rabbit was investigated. Six rabbits per test group were used to do digestion trial. Nutrient digestibility was determined in rabbit diet with total fecal collection method. Results showed that digestibility of dry matter, protein and crude fiber decreased for group III rabbits, however, no difference was found for other groups.In Experiment 3, effect of papaya powder on meat quality and development of digestive tract was investigated in New Zealand white rabbit. Six rabbits per test group were used to do slaughter test. Results showed that papaya powder has little effect on meat quality and development of digestive tract. added 5%and 8%pawpaw powder to improve dressing percentage and ratio, however, there is no difference between test sets.In Experiment 4, effect of papaya powder on reproduction and lactation performance was investigated in New Zealand white rabbit. Forty eight rabbits with similar reproduction performance were randomly divided into 3 groups (group I, II and control). Five and ten percent of papaya powder was fed in rabbit diet of group I and II, and no papaya powder in the control. Results showed that, compared with the control, the number of rabbit cubs and survival cubs per litter, slightly increased in test groups. Average litter weight at birth increased by 13.4%, and 11.5%in group I and II rabbits compared with the control (P<0.05). And average lactation yield of rabbits in group I and II increased by 9.2% (P<0.05),8.8%(P<0.05). Average litter weight at weaning increased by 12.0%(P<0.05),12.6%(P<0.05) in group I and II rabbits compared with the control. There was no difference for above indicators between groups I and II. In assay for determination of prolactin, average level of E2 increased by 54.6%(P<0.05),58.4%(P<0.05) in group I and II rabbits compared with the control and average level of PRL increased by 85.0% (P<0.05). There was no difference between other groups.In conclusion, when papaya powder added at an optimal concentration of 5%in ration of rabbit, it is beneficial to improve growth, reproduction and immunity of New Zealand white rabbit. It is also beneficial to cut down the cost and reduce usage of antibiotic and improve social and economic benefit.