Productive and reproductive performance of rabbits fed diets supplemented with zinc methionine

الملخص EN

A total number of three hundreds and twenty four Californian(Cal) rabbits was used in the present work to study some productive and reproductive performance of growing and mature rabbits as influenced by supplementing Zinc-Methionine to the diets.

The present study included two experiments.

The first experiment was lasted 40 days and carried out during growing period on 230 weaned Cal rabbits aged 30 days.

The second experiment was lasted 4 months and carried out on 80 monoparous does and 14 sexual mature bucks of Cal rabbits aged 6 months.

All rabbits in two experiments were divided into two equal comparable experimental groups (115 growing rabbits, 7 bucks and 40 does in two sequence parities in each group).

The first group was kept untreated (as a control group) and fed the commercial diet, while the other group (treated group) was fed the same diet and supplemented with 400 gm/ Ton Zinc-Methionine (ZM), during the experimental period.

The pelleted rations fed to the experimenta lrabbist were covering the nutritional requirements of the growing and mature phase of rabbits..

The results obtained revealed that, daily body weight gain , feed efficiency and feed conversion values of growing Cal rabbits fed diet supplemented with 400 gm/ Ton Zinc-Methionine significantly (P<0.05) improved.

Daily feed intake was insignificantly higher than those of control group.

Feeding diet supplemented with 400 gm/ Ton Zinc-Methionine increased significantly (P<0.05) dressing % and carcass and internal organs weight (absolute and relative) represented by weights and percentages of each of spleen; kidneys; liver; heart and lungs, as well as, blood picture of growing Cal rabbits represented by (red and white blood cells count; hemoglobin concentration and hematocrite percentage) and some blood constitute such plasma total protein and its fractions (albumin; globulin and albumin/ globulin ratio).

Some enzymes indicated liver activity of growing Cal rabbits represented by values of each of glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) also increased significantly (P<0.05) due to supplementation of 400 gm/ Ton Zinc-Methionine to the diet.

Supplementing 400 gm/ Ton Zinc-Methionine to the diet of the Cal rabbit bucks improved significantly (P<0.05) their reproductive capability represented by libido and physical semen quality (semen-ejaculate volume; advanced-sperm motility; live and normal spermatozoa; acrosome status and sperm-cell concentration per ml and per ejaculate); gonads and pituitary gland weight; scrotal circumference and testicular index.

Testosterone concentration and mating activity of Cal rabbit bucks ate diet supplemented with 400 gm/ Ton Zinc-Methionine were significantly (P<0.05) higher than those of fed without Zinc-Methionine (control group).

Cal rabbit does fed diet contained 400 gm/ Ton Zinc-Methionine and mated naturally by using bucks fed the same treated diet recorded kindling rate, litter size and weight at birth; milk yield and pre-weaning mortality rate significantly (P<0.05) better than those of received untreated diet (control group).

It can be concluded that supplementation 400 gm/ Ton Zinc-Methionine to Cal rabbit diet showed a great role in enhancing the immune system, improved growth performance, blood metabolites and reproductive performance.

From the economic point 400 gm/ Ton Zinc-Methionine is recommended for both growing and mature (bucks + does) rabbits.

Key words: rabbits; Zinc-Methionine; blood; carcass; performance, semen, fertility.