الفهرس 
Performance of broiler chickens in response to dietary inclusion of copper nanoparticles and some yeast products
AbstractOnly 14 pages are availabe for public view
 |  | from | 177 |  |  |
| | | from | 177 | | |
Abstract
This thesis comprises two studies evaluating a couple of dietary manipulations with broiler chickens. In trial (I), a 37-day length comparative study was performed with Arbor acres broilers to assess the outcomes of different inclusion levels of copper nanoparticles (Cu-NPs) with an average particle size of 72.4 nm, Cu-NPs were laboratory prepared and characterized via a chemical reduction method. The effects of Cu-NPs were compared to those of the inorganic copper sulfate (Cu2SO4) on the growth performance and feed utilization indicators, carcass traits, serum antioxidant biomarkers (total antioxidant capacity (TAC), malondialdehyde (MDA), and superoxide dismutase enzymatic activity (SOD)), copper (Cu) tissue concentrations (serum, liver and breast muscle) and the transcriptional fold changes of metallothionein(MT) and ceruloplasmin (CP) genes of broiler chickens. A total of 192 one-day-old, as-hatched broiler chicks with an average body weight of 39.1± 0.8 g were distributed into four equal groups in a random way. Each group was further split into four replicates with 12 chicks per replicate. The experimental design was arranged as the following strategy: the first group (G1) was utilized as the negative control group which has been supplemented with a Cu-free premix, and the second one (G2) has been provided with the common Cu sulfate-containing premix at the level of 2500 mg/kg of premix, whereas the third and the fourth groups (G3 and G4) have been received premixes compromise Cu nanoparticles at the inclusion levels of 2500 mg/ kg and 1250 mg/ kg of premix, respectively. All the experimental premixes were added at the level of 3 kg/ ton of diet. Subsequently, the Cu supplementation in the diets of birds was G1: zero mg/ kg, G2: 7.5 mg/ kg, G3: 7.5 mg/ kg and G4 3.75 mg/ kg of diet. The Cu content in feed ingredients of the diets (without Cu supplementation) of all groups was determined to be 3.83 mg /kg. Results of the growth performance have shown that Cu-NPs at the level of 7.5 mg/ kg of diet have significantly (P ≤ 0.05) improved body weight gain and feed conversion ratio (FCR) compared to the equal quantity of Cu2SO4. No deteriorating impacts on either the growth performance or FCR occurred when Cu-NPs were supplemented at half of the recommended level of Cu2SO4. The dressing and thigh muscle yields have been significantly (P ≤ 0.05) elevated in the birds in G4 relative to other birds. Meanwhile, the TAC and MDA levels as well as the transcription of CP have not been significantly influenced as a result of various sources and levels of Cu supplementation, under the conditions of our study. The SOD’s enzyme activity and mRNA level of the MT gene have been significantly (P ≤ 0.05) increased by the replacement of Cu2SO4 with the same quantity of Cu-NPs. In a similar pattern, the concentrations of Cu in the serum of the Cu-supplemented birds have significantly (P ≤ 0.05) increasedwhen comparedto those birds in G1.Wherethe largest serum and breast concentrations of Cu (P ≤ 0.05) have beenfound in birds in G3. All groups have exhibited significant (P ≤ 0.05) differences in the hepatic deposited Cu. An order of the retained hepatic Cu has been significantly (P ≤ 0.05) determined, which was as follows: G3, G4, G2 and G1, respectively (from high to low). Therefore, our findings have indicated that Cu-NPs could be a superior dietary supplement of Cu in broiler chickens’ diets over Cu2SO4, with the possibility of quantity reduction without jeopardizing the broiler chickens’ productivity and wellness.In trial (II), a feeding experiment was conducted toinvestigate the influences of the dietary fortification of broiler chickens with the Saccharomyces cerevisiae’s cell wall (YCW), cell extract (YCE) and a yeast-derived blend (YDB) on the growth performance, feed efficiency, carcass characteristics, histo-morphological picture of the gut jejunal mucosa, liver antioxidant biomarkers (total antioxidant capacity (TAC), glutathione peroxidase (GPx) and malondialdehyde (MDA)) and antibody production against Newcastle Disease viruses (NDV). Thus, a total of 1200 mixed-gendersArbor acres broiler chicks at the age of one day, with an average body weight of 42.8 ± 0.94 g were randomly divided into four groups. Each group was subdivided into six replicates, each replicate included 50 chicks. Birds in the first group (G1) have consumed plain basal diets (Negative control). Whereas the basal diets of treatment groups were fortified with yeast-based products each at the level of 1 g/kg. where the diets of birds in the second group (G2) were enriched with YCW, and birds in the third group (G3) have been fed on diets empowered with YCE. A yeast-derived blend (YDB) which was composed of YCW and YCE (1:1) was added to the diets of birds in the fourth group (G4). The outcomes of the study have included that the feed intake of all birds has not been significantly changed. While the birds which have been exposed to the dietary fortification with YCW (G2) significantly (P ≤ 0.05) achieved better final body weight and body weight gain and feed conversion ratiocompared to those in other groups. The dressing and breast yields of birds in G2 were significantly (P ≤ 0.05) higher than in other birds. The evaluated yeast-derived products at the level of 1 g/ kg have not induced a significant response in TAC and GPx levels in the liver extracts of all birds. However, the level of the MDA has been significantly (P ≤ 0.05) decreased in the livers of broiler chickens supplemented with YCW compared to other birds. There was a significantly (P ≤ 0.05) higher number of antibodies against NDV in the serum of birds in G2. The villus height: crypt depth ratio in jejunum exhibited a significant (P ≤ 0.05) optimization in YCW and YDB supplemented groups (G2 and G4), as well as higher jejunal mucosa intactness, which were shown in the same groups in comparison to G1 and G3. Our findings have concluded that YCW could be anefficient dietary yeast-originated additive in broiler chickens’ diets over YCE and YDB. Moreover, YCE fortification may be an unrealistic approach for improving the broiler chickens’ performance.