The effect of different levels of saponin on digestibility, ruminal and blood parameters in Baluchi male sheep

Due to the recent drought condition and rising cost of production, the productivity of any feedstuff that can be used to feed livestock has become inevitable. The use of agricultural residues, while estimating some of the needs of low-cost livestock, often faces problems such as the presence of anti-nutritional compounds such as tannins and saponins. This experiment was designed and performed to investigate the effect of saponin on fermentation, functional and metabolic parameters of Baluchi sheep.

This experiment was performed using 3 Baloch male sheep with an average live weight of 40±2 kg, which were about 9 months old, in the form of a change over design in three 21-day periods including 14 days of adaptation and 7 days of sampling period. Experimental treatments including; Different level of pure saponin in proportions of 0, 60 and 120 mg / kg dry matter were added to the feed. The ration used was adjusted based on the nutritional needs of Baluchi male sheep using SRNS software version 2007, which included a mixture of forage and concentrate in 50:50 ratios. The rations were thoroughly mixed and provided to the animals in two meals in the morning (08:00) and in the evening (20:00). The animals had free access to water and feed during the experimental period. The obtained statistical data were evaluated in the form of a change over design using SAS 9.1 software. Blood sample were harvested from jugular vein for serum blood metabolites. To collect plasma, blood samples were transferred test tubes and after 15 minutes at room temperature, centrifuged (for 15 minutes at 1509 xg) and their plasma was collected, then transferred to sterile microtubes. Serum was stored in -20 centigrade until further analysis.

The results of the above experiment showed that the addition of saponin had no significant effect on the apparent digestibility of dry matter, organic matter, crude protein, insoluble fibers in neutral detergent (NDF) and insoluble fibers in acidic detergent (ADF). Data indicated that experimental treatments could not have a significant effect on the urea, triglyceride and blood glucose levels. The amount of cholesterol in the blood was affected by saponin so animals received 60 or 120 mg saponin had a significantly lower cholesterol than control group (p>0/05). Although ammonia nitrogen during pre-feeding and 2 or 4 h after feeding was not affected by treatments but in overall the mean ammonia was affected by saponin level, so by increasing saponin in diet trend was to decrease of ammonia nitrogen compare to control group. Accumulation of saponin in rumen cause to alter rumen environment and decrease its pH in Baluchi sheep.

The results of the present experiment showed that increasing the amount of saponin in the diet reduced the nitrogen level of ruminal urea and some blood parameters, which can have destructive effects on animal growth. Increasing saponin to levels above 60 mg / kg of dry matter in the diet has led to a significant reduction in blood cholesterol. Based on the data of this experiment and the results reported in different experiments, it is recommended that the using feed contained saponin be targeted and limited as a feed, to reduce the side effects on the animal performance and health.