پديد آورندگان :
عظيمي يوالاري، صبا دانشگاه اروميه - دانشكده ي كشاورزي - گروه علوم دامي , فرهومند، پرويز دانشگاه اروميه - دانشكده ي كشاورزي - گروه علوم دامي , پيوستگان، سينا دانشگاه اروميه - دانشكده ي كشاورزي - گروه علوم دامي , باغبان كنعاني، پيام دانشگاه تبريز - دانشكده ي كشاورزي - گروه علوم دامي
چكيده لاتين :
Introduction: The name canola was adopted for the double low varieties of rapeseed in 1979. By definition Canola seeds contain less than 2% and 30 μmoles for erucic acid and glucosinolates in defatted meal, respectively. Although the United States Department of Food and Drug Administration recognised Canola as a separate species, in the scientific writings the names canola and double low or double zero-rapeseed are used interchangeably (Zeb 1998). Glucosinolates are secondary plant metabolites that occur in all Brassica-originated feeds and fodders. Content and composition of Gls vary due to plant species, agronomic practices and climatic conditions (Tripathi and Mishra 2007). Glucosinolates are present in all plant parts and are physically separated from the enzyme myrosinase. Injury of plant tissues during processing or ingestion facilitates the contact between Glucosinolates and myrosinase enzyme. The Glucosinolates are then hydrolysed by both myrosinase enzyme present in plant and myrosinase produced by intestinal microflora, to release a range of breakdown products (Tripathi and Mishra 2007).
Material and methods: A total of 405, 1-d-old male broiler chicks (Ross 308) obtained from a local hatchery and randomly allotted to 1 of 45 floors pens (with 5 replicates and 9 chicks in each replicate) measuring 1.5 m2. The 1-d-old Chicks were weighed individually and allocated to pens so that their initial weights were similar across all pens. Three levels of treated Canola meal with copper sulphate (0, 125 and 250 mg/kg) and Arginine (0, 0.1 and 0.2%) in a 3×3 factorial design and nine dietary combinations in equinitrogenous and equicaloric diets (Table 1). The basal diets were formulated according the Ross requirements (Aviagen Company) guideline. The nine treatment diets were 1) 0 mg/kg of copper and 0 % of Arg , 2) 0 mg/kg of copper and 0.1 % of Arg, 3) 0 mg/kg of copper and 0.2 % of Arg, 4) 125 mg/kg of copper and 0 % of Arg, 5) 125 mg/kg of copper and 0.1 % of Arg, 6) 125 mg/kg of copper and 0.2 % of Arg, 7) 250 mg/kg of copper and 0 % of Arg, 8) 250 mg/kg of copper and 0.1 % of Arg, 9) 250 mg/kg of copper and 0.2 % of Arg. All chicks were provided ad libitum access to water and their assigned diets (in mash form). Source of copper was sulfate pentahydrate (Merck Company, Germany) and after calculating, the purity was added to basal diets. The experiment lasted for 21 d (21-42 d), and 24 h of light was provided throughout the experiment. Throughout the trials, feed was weighted when delivered and when mortality occurred. Based on the recorded data, feed intake (FI), feed conversion ratio (FCR), body weight (BW) and body weight gain (BWG) were calculated. On day 42 of Trial, one bird per pen were randomly selected and commercially slaughtered for whole carcass analysis after 12 hours of fasting. After slaughter, the organs such as breast, thigh, drumstick, abdominal fat, lungs and intestine were weighted. For treating canola meal with copper sulfate ion, spray method was used. At first, canola meal were milled by grinder, then 1.47 and 2.93 grams of copper sulfate Pentahydrate is completely dissolved in 900 cc of water (per kg of canola meal) and were sprayed uniformly on canola meal. Treating canola meal was heated for 24h at 60°C until to ensuring constant weight. After complete drying, canola meal treated with copper, ready to mix with other part of experimental diet (table 4). The experiment was conducted using completely randomized design with factorial structure. Data were subjected to ANOVA using the GLM procedure (SAS, version 9.1) as a 3×3 factorial, with the main effects of copper and Arginine, and the Arginine × copper interaction. Significant means among variables were separated by Duncan's multiple range tests at 5% level of significance.
Results and discussion: Average daily gain and feed conversion ratio were significantly affected (P<0.05) by 250 mg/kg copper treatment. Canola meal treatments with Cu (P<0.01) and addition of 0.2% Arg (P<0.05) significantly increased proportion of breast muscle. Also the use of 0.2% Arg significantly declined proportion of abdominal fat (P<0.01) and lungs weight (P<0.05) and conversely increased proportion of duodenum (P<0.05) and jejunum (P<0.01). Cecal relative weight was observed the lowest (P<0.05) for birds fed diets based on canola meal treated with 250 mg/kg Cu. Birds fed diets which supplemented by 0.2% Arg had lower (P<0.01) plasma uric acid concentration versus other supplemmetation levels. The broiler chick's nutritional requirement for copper is approximately 8 mg/kg (NRC 1994). Various processing techniques were applied to remove glucosinolates in order to minimize their deleterious effects on animals. One way to reduce the deleterious effects of glucosinolates in monogastric diets, supplementation with metal salts (Tripathi and Mishra 2007). The growth stimulation effects of Cu could be attributed to shifting the gastrointestinal microbiota, thereby reducing susceptibility of birds to disease, reducing intestinal lymphocyte recruitment and infiltration, and thus increasing nutrient absorption. Interestingly addition of Cu sulfate could improve intestinal mucosal-morphology, which may contribute to improve nutrient availability and is associated with increasing goblet cell numbers, total goblet cell area, goblet cell mean size, mucosal thickness and a greater number of segmented filamentous bacteria compared with controls (Payvastegan et al. 2013). Khajali et al (2013) demonstrated that supplementation of broiler diets with 1% arginine, despite any change in performance, enhanced the length and width of villus in the jejunum.
Conclusions: In conclusion, the results of this study showed that treatments of canola meal with Cu could alleviate adverse effects of glucosinolate on broilers performance. Moreover, these findings suggested that addition of 0.2% Arg able to change energy metabolism toward protein deposition.
