The Effects of replacing soybean meal with different levels of processed corn steep liquor on growth performance, ruminal parameters and purine derivatives of Lori Bakhtiari lambs

Provision of food in a fattening period includes about 65 to 70% of the costs related to livestock breeding and maintenance. The most important issue in preparing the ration is choosing raw materials with high availability, cheap price and nutritional value to meet the recommended nutritional needs of each type of livestock. corn steep liquor is one of the industrial wastes, which is produced during the wet milling process of corn kernels for the extraction of corn starch and oil. Processing is one of the ways to change and improve the nutritional value of grains, especially starch and protein. Among the reasons for using corn steep liquor, we can mention the high nutritional value of corn steep liquor (high protein content), the level of corn steep liquor production in the country and the cheap price of this by-product.

The aim of this experiment was to evaluate the effect of aldehyde-treated corn steep liquor on soybean meal on growth performance, ruminal parameters and purine derivatives of fattening lambs. 37% formalin at a concentration of 3.5% was used to process corn steep liquor. Twenty-five male Lori Bakhtiari lambs with an average weight of 26±3 kg and an age of about 3 months were allocated in a 105 day period (15 days of adaptation and 90 days of the main period) in a completely randomized design with 5 experimental treatments and 5 replications. Experimental treatments included soybean meal with different levels of corn steep liquor processed with formaldehyde (0, 25, 50, 75 and 100%) replaced in the diet.

The highest body weight, daily feed intake and daily weight gain were related to lambs fed with 100% Formaldehyde-processed corn steep liquor and the lowest feed intake and daily daily weight gain. It was related to lambs fed with control treatment (P<0.05). The feed conversion ratio improved but did not increase with increasing the level of formaldehyde-treated corn steep liquor. With increasing the amount of formaldehyde-treated corn steep liquor in the diet, the pH of the lambs rumen decreased significantly (P<0.05). In all experimental diets, ruminal fluid ammonia concentration was reported in the optimal range (8.5 to more than 30 mg/dL). Total concentrations of volatile fatty acids, acetate, propionate and butyrate density, acetate to propionate ratio in ruminal fluid of experimental animals fed a diet containing formaldehyde-treated corn steep liquor were not affected by the experimental diets. However, the ruminal density of valerate and isovalerate decreased significantly with increasing the salinity of formaldehyde-processed corn steep liquor (P<0.05). Excretion of each purine derivative (allantoin, uric acid, xanthine + hypoxanthine) and total excretion and absorption of purine derivatives from urine and the amount of microbial protein produced in the rumen were affected by experimental diets and the observed difference was significant. (The control treatment showed the highest and the 100% level treatment of formaldehyde processed corn steep liquor showed the lowest) (P<0.05). Urinary excretion of nitrogen decreased with increasing fat content of formaldehyde-treated corn steep liquor in the diet.

The results of the present experiment showed that the use of formaldehyde-processed corn steep liquor in lambs diet, body weight, daily dry matter intake and daily weight gain, increase and amount of ammonia, pH, valerate and isovalerate fatty acids and microbial protein production Reduces rumen in lambs and reduces the breakdown of protein in the rumen, and the feed protein is broken down in the small intestine and the use of formaldehyde-treated corn steep liquor with soybean meal has no adverse effect on livestock performance.