عنوان مقاله [English]
Background and purpose: Pregnancy duration is divided into 3 phases in goats including: day 0 to 50, 50 to 100, and > 100). Transition period is accompanied by metabolic disorders which are minimized by dietary grain and digestible energy concentration. Nutrition can have beneficial effects on the incidence of milk fever in early lactation in the transition period. Animals often face with hypoglycemia and hyperlipidemia in during transition period. Excessive consumption of starch carbohydrates such as barley and maize by the ruminant causes acute or chronic acidosis, so replacing starch with other energy sources such as fibers or fats while supplying the energy needed to handle starch problems For the livestock. In the recent years, new technologies and techniques initiate innovation. Food ingredients are being developed that possess superior functional properties in livestock, because of their role in maintain of health, growth, safety and reproduction. Nutrition is known as one of most important factors influencing and can have beneficial effects on fertility. One of promising strategies is feeding of fatty acids and sources of triacylglycerols (TAG). It is well-known that the n-3 fatty acids are necessary in mammals, especially for the fetus. It is well-known that the n-3 fatty acids are necessary in all mammals, especially for the fetus and the neonate. It is known that lipid supplementing improves energy balance and enhances the overall dietary energy content and finally promotes milk production. Omega-3 fatty acids are known to have antioxidant effects that play a critical role in the development and functioning of the central nervous system. There is no any data in literatures on the effect of non-fiber carbohydrate sources and saturated and unsaturated fatty acids on productive and metabolic parameters in Mahabadi lactating goats. It was hypothesized that non-fiber carbohydrate sources and saturated and unsaturated fatty acids may alleviate adverse effects of productive and metabolic parameters in Mahabadi lactating. Thus, for first time, this study evaluated the effects of feeding non-fiber carbohydrate sources and saturated and unsaturated fatty acids on productive and metabolic parameters in Mahabadi lactating goats during transition period.
Material and Methods: In this study, twenty multiparous Mahabadi goats with body weight ranged from 47 to 50 kg and age range of 3-4 years were used. Goats were randomly allocated into 1 of 4 dietary treatments with 5 animals in per treatment in a completely randomized design. Animals were randomly allocated into 4 treatments based on age, body weight, and parity. Experimental treatments were including 1) Starch diets with 3 % DM palmitic acid, 2) Starch diet with 3% DM omega 3, 3) diet containing beet pulp with 3% DM palmitic acid, 4) diet containing beet pulp with 3% DM omega 3. The isocaloric and isonitrogenous diets were formulated based on NRC (2007) by SRNS software. Feed samples were fined by a Wiley mill by using a 1-mm screen and analyzed for dry matter (DM), ash, crude protein (CP), crude fiber (CF), and ether extract. Neutral detergent fiber (NDF) and acid detergent fiber (ADF) were assessed by Van Soest et al. (1991). All analyses were conducted twice. Milk composition including fat, protein, and lactose was measured by Milko & Scan apparatus. Serum total protein, total cholesterol, triglycerides, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were determined using commercial kits (Pars Azmoon-Iran). Serum proteins were isolated in order to evaluate the protein fractions into albumins, α1, α2, β1, β2 and γ-globulins (γG). At same days, serum immunoglobulin G (IgG) was measured using the kit from Binding Site Ltd. (Birmingham, UK). This experiment was conducted by Factorial design based on complete randomized design in 9.4 version of SAS software. Duncan procedure was used to evaluate the data. The data were analyzed by SAS software and Duncan test. Statistical model used were as follows;
Where Yij is observations, μ is mean, Aj is effect of carbohydrate sources, Bj is effect of fatty acid sources, ABij is interaction effect of fatty acids and carbohydrate and eij is error effect.
Results: Results indicated that omega 3 diets (diets 2 & 4) could increase milk production, milk fat, milk protein and total solids in comparison to palmitic acid diets (diets 1 & 3) (p < 0.05). However, it was no observed significant difference between diets 2 and 4 for milk production, milk fat, milk protein and total solids (P>0.05). More ever experimental diets did not affect production of fatty acids C4:0 up to C10:0, C14:0, C14:1, C16:1 and C18:1 (P>0.05) but providing diets 2 & 4 decreased production of fatty acids C12:0, C16:0 and C18:0 and also increased production of fatty acids C18:2, C18:3, C20:0, C20:2 and C22:0. It was no observed significant difference between diets 2 & 4 for mentioned fatty acids. Providing diets to goats did not have significant effects on total protein, albumin, , β and γ protein (P>0.05). The serum concentrations of cholesterol, triglycerides, AST and ALT were decreased in goats fed with diets 2 & 4. However, goats receiving the diet 3 also showed lower levels for liver enzymes (p < 0.05). Goats fed with diets 2 & 4 showed higher titer for IgG in comparison to other treatments (p < 0.05).
Conclusion: Dietary inclusion of omega 3 with and without non-fiber carbohydrate could improve milk production and composition. It also improved lipid profile in milk and serum, liver enzymes and immunity. It can be recommended to use omega 3 in order to improve the milk composition, milk production and immunity in goat in transition period. In general, it can be concluded that omega 3 oils can have beneficial on productive and blood parameters.