عنوان مقاله [English]
Introduction: Harmful effect of antibiotics is evident in the feed industry. This industry needs an alternative instead of growth-promoting antibiotics. Medicinal plants can be the alternative due to their antimicrobial and nutritional effects. Coriander (Coriandrum sativum L.) is one of the medicinal plants used in animal and poultry nutrition. Coriander seeds’ essential oil is rich in oxygenated monoterpenes. In addition to camphor, granil acetate, alpha-pinene, graniol, and pisimin are other predominant constituents of coriander seed’s essential oil. Minerals including phosphorus, calcium, potassium, and essential amino acids including glutamine, asparagine, and arginine have also been identified as components of coriander seeds. The main component of coriander seeds is linalool. The effect of using coriander seeds and its positive effects on yield, rumen fermentation process, blood parameters, meat quality, and feed conversion ratio has been reported in sheep of different breeds. Therefore, this study aimed to investigate the effect of adding coriander seeds to the diet on yield, nutrient digestibility, and blood parameters of Sanjabi lambs.
Materials and methods: 16 male lambs with 90 days of age (weaning age) and an average weight of 27±1.5 kg were considered in this study. Fattening was done for 90 days. Lambs were also vaccinated against enterotoxemia. Diets contained the concentrate to forage ratio of 70 to 30. Diets included 0 (without medicinal plants), one, three, and five percentages of coriander seeds. During the fattening period, water and feed were ad libitum to the lambs and the feed was distributed three times a day. Lambs were weighed at the beginning of the period and then monthly after 14 hours of starvation. The dry matter intake was measured daily and the average daily weight gain and feed conversion ratio were calculated at the end of the fattening period. To prepare a stool sample for each head of lamb, five daily stool samples were mixed in equal value and thus a sample was prepared for each lamb. At the end of the rearing period, the fecal collection was performed directly from the rectum of the lamb for five consecutive days. Stool samples were collected from the rectum every three hours and immediately transferred to a refrigerator at 4 °C. The statistical analysis of data was conducted in a completely randomized design using the GLM procedure of the SAS program. Also, Duncan’s multiple range test was used for the comparison of treatment means.
Results and discussion: The digestibility of dry matter, crude protein, ether extract, and insoluble fibers in neutral detergent (percent) was the same in different treatments (P>0.05). Creatinine, albumin, total globulin, glucose, total protein, cholesterol, triglyceride, urea, beta-hydroxybutyrate, aspartate transaminase, and alanine transaminase were not affected by experimental treatments during feeding (P>0.05). None of the blood serum metabolites of lambs was affected by coriander seed ((P>0.05). The results showed that consumption of coriander seeds had a significant effect on dry matter intake and daily weight gain (P<0.05). The best feed conversion ratio was obtained in the treatment containing one percent of coriander seeds (P<0.05). Compared to the control diet, diets containing coriander seeds had a significant effect on the apparent digestibility of calcium and phosphorus (P<0.05). Using coriander seeds in the diet made a decrease in blood urea nitrogen and increased blood glucose during the fattening period, but did not affect other blood metabolites. Concentrations of liver enzymes including aspartate aminotransferase and alanine aminotransferase tended to be increased by five percent of coriander seed in the diet compared to the control treatment, indicating liver activity to remove toxic effects and anti-nutrients components. Coriander seeds have strong antioxidant properties due to compounds such as riboflavin, tocopherol, total polyphenols, gallic acid, caffeic acid, and quercin. In the present study, blood cholesterol decreased by increasing coriander seeds in the diet. This may be due to a decrease in the activity of the cholesterol-synthesizing enzyme in the liver, making a decrease in tissue cholesterol, and the ratio of unsaturated to saturated fatty acids by aging.
Conclusions: According to the obtained results, it can be concluded the use of one to three percent of coriander seed in the diet of fattening lambs improved the performance, and apparent digestibility and has positive effects on blood metabolites including glucose and urea nitrogen in Sanjabi lambs.