Research On Animal Production

Extended Abstract

Background: The domestic rabbit, Oryctolagus cuniculus, from the Leporidae family, is a herbivorous mammal whose usual diet consists of plant sources. Rabbits can tolerate temperatures between 4 and 27 degrees Celsius; however, the recommended average temperature for them is between 16 and 22 degrees Celsius. The average gestation period for rabbits is 28 to 31 days. The type of forage in rabbit diets significantly affects their growth performance. Rabbits require energy, fiber, and protein in their diets. It is recommended to use both fodder plants and tropical plants for rabbit feeding. Currently, dry fodder, such as alfalfa, constitutes 40 to 80% of a rabbit's diet. High-energy plants like corn, wheat, barley, and alfalfa are commonly consumed. However, the high prices of alfalfa and barley increase feed costs, which in turn reduces economic efficiency. Tropical plants, such as Conocarpus erectus and myrtle, contain significant amounts of protein, fat, minerals, and carbohydrates that can positively influence growth and production. Conocarpus erectus is a common ornamental plant in tropical and semi-tropical regions, typically reaching heights of 1.5 to 4 meters. This plant contains bioactive compounds such as alkaloids, saponins, tannins, phenolic compounds, resins, terpenes, glycosides, and exhibits antibacterial activity. The myrtle plant is a small shrub with evergreen leaves, containing effective substances like phenolic acids (gallic acid, vanillic acid, and ferulic acid), tannins, catechins, and quercetin. Therefore, the purpose of this experiment was to assess the effects of incorporating myrtle and Conocarpus plants into the diets of first-generation rabbits on digestibility, antioxidant capacity, blood parameters, and the microbial population of the digestive tract.
Methods: In this project, 12 breeding rabbits of the New Zealand breed (10 females and 2 males) were tested. After a 28-day gestation period and a 30-day lactation period for the newborn rabbits, the designated treatments were applied to the litters (each treatment consisted of five repetitions). The treatments included: 1) control treatment, 2) treatment receiving 25% myrtle plant, and 3) treatment receiving 25% Conocarpus plant, arranged in a completely randomized design. The experiment was conducted on the newborn rabbits for 30 days, with an average weight of 250 grams. At the end of the experiment, the digestibility of dry matter, crude protein, insoluble fibers in neutral detergent, insoluble fibers in acid detergent, and antioxidant activity of the meat during storage in the refrigerator and freezer were measured. Additionally, the microbial population of the digestive tract (including Lactobacillus, E. coli, and coliform bacteria) and blood parameters (cholesterol, triglycerides, low-density lipoprotein, high-density lipoprotein, glucose, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase concentrations) were assessed.
Results: The results indicated that the inclusion of myrtle and Conocarpus in the diet decreased the digestibility of dry matter, crude protein, neutral detergent fiber, and acid detergent fiber (P < 0.05). The microbial population results showed that the populations of Lactobacillus, E. coli, and coliforms in the cecum of rabbits fed with myrtle and Conocarpus were not significantly different (P > 0.05). The antioxidant level of the meat during storage indicated that meat from rabbits fed with myrtle had lower malondialdehyde concentrations and greater antioxidant properties compared to meat from rabbits fed with Conocarpus (P < 0.05). Regarding blood parameters, the concentrations of cholesterol, triglycerides, low-density lipoprotein, high-density lipoprotein, and glucose were significantly lower in treatments using myrtle and Conocarpus compared to the control treatment (P < 0.05). However, there were no significant differences in the concentrations of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase among the treatments (P > 0.05).
Conclusion: The results of this experiment demonstrated that incorporating myrtle and Conocarpus plants as substitutes for part of the alfalfa in the diets of newborn rabbits positively affected digestibility, malondialdehyde concentration, and blood parameters. Given the positive effects of these plants on the antioxidant concentration of rabbit meat during storage, as well as on blood biochemical parameters, and considering the affordability and availability of these plants in certain regions, particularly in Khuzestan, it can be concluded that including 25% myrtle and Conocarpus in rabbit diets can serve as an effective antioxidant and herbal supplement.