Effects Of Mulberry Leaves On Production Performance、Slaughter Performance And Meat Quality In New Zealand White Rabbits

In order to study the effect of mulberry leaves powder on growth performance, slaughter performance, serum biochemical indexes and meat quality in New Zealand white rabbit, different levels of mulberry leaves powder were added to rabbit diet to accelerate the abundant resources about effective development and utilization of mulberry. This experiment was conducted using a total of 120 New Zealand white rabbits keeping for 35 days, which were randomly divided into four treatment groups (30 for each treatment,10 for each replicate half were male and the other half were female). Mulberry leaves powder added levels were 0% (control group),15% (experimental group Ⅰ),20% (experimental group Ⅱ),25% (experimental group Ⅲ)with the trial period 35d. The results showed as follows:1. New Zealand white rabbit production and carcass performance results showed that adding 15% mulberry leaves powder to New Zealand white rabbits diet had a significant effect on weight gain, which group Ⅰ final weight and average daily gain was significantly higher than the control group (P<0.01). The feed gain ratio of group Ⅰ was dramatically lower than the control group (P<0.01), but in the entire experimental period there was no significant difference in dry matter intake (P>0.05). Slaughter weight in the control group, the group Ⅱ and group Ⅲ were not significantly different (P>0.05), but were significantly lower than group Ⅰ (P<0.01). The eviscerated rate and semi-eviscerated rate of the control group had no significant difference with group Ⅰ, group Ⅱ (P>0.05), but significantly higher than group Ⅲ (P<0.01).2. The concentrations glucose, cholesterol, triglycerides and urea nitrogen of each experimental group showed the trend greatly lower than the control group (P<0.05), while serum total protein had no sensible difference between each experimental group and the control group (P>0.05). The results of serum antioxidant index showed that mulberry leaf powder added to the diet had no significant effect on the New Zealand white rabbit serum SOD (P> 0.05). With the increasing proportion of mulberry leaf powder, each test group CAT content decreased, group I and control group was significantly different (P<0.01). MDA content in the control group was higher than each test group and had significant difference with group II (P< 0.05). Experimental group of T-AOC upward had an increasing pattern, which were higher than the control group. Immune indexes in serum result showed that, with the increasing proportion of mulberry leaf powder, each test group content of serum ACP and IL-6 were increased than those in the control group, and gradually reduced. The increasing pattern in the test group of LMZ, were greater than in the control group (P<0.05). There was no significant difference between control group and the experimental group content of IL-2 (P>0.05).3. Conventional meat quality results showed that in longissimus muscle and leg muscle the experimental group of L* value and a* values were greater than in the control group (P<0.05), the rate of water loss and shear force were less than the control group, while the difference of b* values and the pH between each experimental group and control group were not significant (P> 0.05). The results of the chemical composition in muscle showed that the moisture content of group II in longissimus muscle was significantly lower than the control group and the group III (P<0.01), the moisture content of group I in leg muscle was significantly lower than the control group and the group II (P<0.01). With the addition ratio of mulberry leaf powder increased fat content of each experimental group were decreased, while crude protein content showed an increasing pattern in varying degrees, crude ash of each test group showed no significant variation.4. The results of muscle flavor, freshness indicators and other the chemical constituents showed that the IMP content of the control group in longissimus muscle was significantly lower than group I and group II (P<0.05). The IMP content in leg muscle were on the rise with the increase proportion of mulberry leaf powder, the control group were significantly lower than group II and group III (P<0.05). The results of amino acids showed that in the longissimus muscle and leg muscle aspartic acid, glutamic acid, Leucine and lysine were subject of its amino acid composition, the group I and group II measured essential amino acids, delicious amino acids and amino acids total content were higher than in the control group, the total amount of amino acids and delicious amino acids content in the longissimus muscle were significantly greater than the leg muscles. It was showed that the flavor and tastiness varied between different part of muscle. Fatty acids results showed that the experimental group content of palmitoleic and oleic acid, with the increasing proportion of mulberry leaf powder decreased. Linoleic and linolenic content of control group were significantly lower than group Ⅰ and group Ⅱ (P< 0.05). The unsaturated fatty acid content in Longissimus muscle and leg muscle were significantly higher than that of saturated fatty acid content. It was showed the meat of group I and group II were better in taste, flavor and more nutritional value.In summary, adding 15%～20% mulberry leaves in the diets could promote the production performance of New Zealand white rabbits, reduce serum main biochemical index content, also different levels enhance the body’s antioxidant capacity and immunity. At the same time, mulberry leaves could improve the flavor and nutritional value of meat to some extent.