Effect of replacing dietary alfalfa with barberry leaf on growth performance and blood indices in ostrich

Introduction: The term “Livestock Revolution” was coined to describe the projected increase in demand for animal products due to population growth, increased income, and urbanization in developing countries. In this context, a decision to rear well-adapted livestock species, like the ostrich, could be effective in meeting present and future demands for animal products in a sustainable manner. On the other hand, most of the ostrich production costs are associated with the feeding price similar to broiler chickens. Due to the high ability of ostrich regarding fiber consumption, it is expected that ostriches can benefit from cheaper native foods such as barberry leaves. Ostrich digestive system has a great ability to use fiber diets due to having a long rectum (about eight meters). Furthermore, the microbial population of the cecum and colon in ostrich is similar to the rumen. The total area of barberry cultivation in Iran was reported to be 16007 hectares in 2017 and more than 14700 hectares of that were placed in South Khorasan. The amount of foliage of each barberry shrub is between three to five kg dry mater which remains almost unused after fruit harvesting. Hence, large amounts of branches and leaves from barberry harvesting could be considered agricultural residues for usage in animal feeding, annually. This study aimed to study the effect of replacing dietary alfalfa with barberry leaf on growth performance and blood indices in ostrich.
Materials and methods: The effects of replacing dietary alfalfa with barberry leaf on ostrich growth performance and some blood parameters were investigated using 20 ostriches (two to seven months of age) in a completely randomized design with five treatments (four replicates each). Barberry leaves and alfalfa used in this study were prepared manually from South Khorasan farms. Then samples were separately pooled and grounded in a hammer mill and were transferred to the laboratory to determine the amount of crude energy, dry matter, crude fat, crude protein, ash, neutral detergent fiber, and acid detergent fiber (all in three replications). The experimental diets were prepared by replacing alfalfa at 0, 25, 50, 75, and 100% with barberry leaf. Diets contain the same metabolizable energy and crude protein. Ostriches had free access to feed and water during the trial. Feed intake and body weight gain of each experimental unit were measured at 60, 120, and 210 days of age, and the feed conversation ratio (FCR) was calculated. At 90 and 210 days of age, blood samples were harvested from the wing vein of ostrich using tubes containing Li-heparin as an anticoagulant, then the blood samples were centrifuged at 3000 × g, 15 min at room temperature, and stored at −20 ^◦C temperature for later analysis. The plasma concentrations of glucose, cholesterol, triglycerides, high-density lipoprotein (HDL), protein, and albumin as well as the activity of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were determined by auto-analyzer spectrophotometry according to the procedures of the manufacturers.
Results and discussion: The results revealed that dry matter intake (DMI) was enhanced with increasing dietary levels of barberry leaf (P<0.05). These findings showed the favorable effects of barberry leaves on feed intake. One of the main reasons associated with the reduction of dry matter consumption following the inclusion of agricultural by-products is the high amount of phenolic compounds, especially the tannins of these products. Barberry leaves have a low concentration of phenolic compounds (especially tannins) compared to other by-products such as pistachio peel, pomegranate pulp, Elaeagnus angustifolia leaves, etc. Substitution of alfalfa hay with barberry leaf at 50% of the diet significantly increased daily weight gain compared to the control group (P<0.05). In the whole experimental period, FCR was lower in the diet containing 50% of barberry leaf than in the diet with 100% replacement of alfalfa with barberry leaf (P<0.05). Increasing the FCR in the diet by replacing more than 50% of barberry leaves can be related to the reduction of the digestibility of the diet due to a decrease in the particle size of barberry leaves as well as its nature after milling compared to alfalfa and the reduction of the supply of amino acid profile due to synergy of two sources of alfalfa and barberry leaves. The highest concentration of plasma glucose at 90 and 210 days of age (191.33 and 193.3, respectively) were observed in the control diet. Numerous studies have reported the hypoglycemic effects of barberry. Replacement of 50, 75, and 100% of alfalfa with barberry leaf decreased significantly the plasma activity of ALT as compared to the control group (P<0.05). Although there are no reports of the use of barberry leaves or its active ingredient (berberine) in ostrich, previous reports have shown that the use of barberry fruit extract reduced liver enzyme concentrations.
Conclusions: Overall, the results of the current study showed that alfalfa hay could be replaced partially or completely with barberry leaves in the diet of ostriches without severe deleterious effects on performance. Replacement of 50% of alfalfa with barberry leaf would recommend for use in ostrich diets.