Journal of Animal Production, Print ISSN: 2008-6776., Online ISSN: 2382-994X

Abstract Objective: Soybean meal is the most commonly fed protein source in ruminant nutrition. Soybean meal protein has moderate ruminal degradability (45-70%) and is deficient in  methionine,. which negatively impacts  the efficiency of nitrogen utilization in the diet and the environmental impact  of excess nitrogen in the urine. This combination of problems, plus market shortages, has spurred the search for suitable replacements for soybean meal. Alternative protein sources such as corn gluten meal and fish meal have a higher rumen-undegradable protein fraction and greater methionine and lysine content than soybean meal. The aim of the present study was to assess the effects of replacing soybean meal partially by corn gluten meal and fish meal on performance, physicochemical characteristics (pH and water-holding capacity, cooking loss) and fatty acid profile of meat in fattening male lambs. Method: A completely randomized design was used to study the effect of three experimental treatments (7 lambs per treatment on feed intake, daily weight gain, and feed conversion ratio (FCR) of 21 male Lori-Bakhtiari lambs (age: 120±15 days, initial weight: 33±2.5 kg) fed individually for 75 days (including a 15-day adaptation period)  with diets containing 13% soybean meal, 5% soybean meal + 3.5% corn gluten meal, or 5% soybean meal + 2% corn gluten meal + 2% fish meal. All diets had aratio of rumen-degradable protein (63%) to rumen-undegradable protein (37%). After slaughter,the physicochemical characteristics and fatty acid profile of the meat were determined. Results: There was no effect of replacing soybean meal with corn gluten and fish meal ondry matter intake. The final weightm daily weight gain  and FCR were all significantly better (P<0.05) for lambs fed a diet containing a mixture of three protein sources (soybean meal+corn gluten+fish meal) compared to other lambs.. Replacing of soybean meal with corn gluten and fish meal did not affect the moisture, fat, and mineral percentages of the lamb meat, but it decreased  the protein percentage of the lamb meat (P< 0.05). The physicochemical characteristics of the lamb meat were also not affected by the replacement of soybean meal with corn gluten and fish meal. Generally, partial replacement of soybean meal by corn gluten and fish meal did not significantly affect the concentration of fatty acids in the meat (as a percentage of total fatty acids) in male lambs, but, the percentages of arachidic acid (C20:0) and docosahexaenoic acid (C22:6) were higher in the meat of lambs fed a diet containing corn gluten + fish meal compared to those fed soybean meal (P<0.05).  Conclusion: Results of the present study revealed that replacing soybean meal with a mixture of corn gluten and fish meal improved growth performance without  affecting the physicochemical characteristics  and the fatty acid profile of the meat in fattening lambs.

Abstract Introduction: Water shortage, low quality soils, and insufficient supply of feed are the main limitations for livestock production in arid and semiarid regions of the word. Therefore, there is a demand to cultivate new crops for these areas as an alternative to crops, which are hypersensitive to low fertile situation. Cultivation of acceptable-quality unusual plants, which are resistant to harsh environmental conditions is a proper way to overcome these challenges. Artichoke (Cynara scolymus L.) is a highly productive crop and produce a large amount of forage per unit of area. Artichoke forage has good nutritional value for ruminant animals. In other hand, artichoke as a medicinal plant contains many secondary compounds including polyphenols, cynarin, chlorogenic acid, carotenoids and natural antioxidants. Lower blood cholesterol and triglyceride and carcass fat have been reported by these compounds in animals fed artichoke products. Therefore, we hypothesized that addition of artichoke forage to diet of fattening lambs may has beneficial effects on their carcass quality traits. Material and methods: In order to evaluate the effects of dietary artichoke (Cynara scolymus L.) level instead of alfalfa on meat fatty acids profile and carcass quality traits of fattening lambs, this experiment was conducted using 24 Kurdish male lambs (initial body weight of 30.2 ± 2.35 kg) in a completely randomized design with three treatments and eight replications. Experimental treatments included: 1) control (diet without artichoke hay), 2) diet containing 10% artichoke hay, and 3) diet containing 20% artichoke hay. The experiment was lasted for 100 days including 20 d of adaptation period and 80 d of data recording and samples collection. At the end of experiment, all lambs were weighed after an overnight fast (16 h). All lambs were slaughtered, and hot carcass were weighed. The carcass was split into two equal halves (left and right). The right half of carcass was cut into six primal cuts including neck, shoulder, breast-flank, loin, leg and tail. Meat chemical composition, color parameters and fatty acids profile were measured. Results and Discussion: The results showed that incorporation of artichoke to the diet improved the daily weight gain of lambs (P<0.05). Also, hot carcass weight and dressing percentage increased linearly with increasing artichoke level in the diet (P<0.05). Dietary artichoke level had no effect on carcass cuts percentage (neck, shoulder, breast flank, loin, leg, and tail), meat chemical composition (moisture, protein, fat and ash) and color parameters (lightness, redness, yellowness). Meat fatty acids profile (including saturated fatty acids, unsaturated fatty acids and conjugated linoleic acids) were not affected by artichoke level in the diets. Conclusion: According to the results, feeding fattening lambs a diet contained artichoke (up to 20% of total mixed ration) has no detrimental effects on meat quality and improve their dressing percentage.