الفهرس 
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Abstract
The current study was conducted at the Animal and Poultry Production research farm, Faculty of Agriculture, Minia University, from April to June 2021.
This study investigated the effects of supplementing 150, 300, and 450 mg/kg of chelated organic zinc amino acids (CH-ZnAA) to rabbits’ diets on some physiological and productive performance. Forty weaned V-line male rabbits were assigned to four equal groups, nominated as T1 (Control, Basal diet without any supplementation), T2 (150 mg Zn/kg), T3 (300 mg Zn/kg), and T4 (450 mg Zn/kg), respectively. The study lasted for 10 weeks.
The statistical analysis was performed using one-way ANOVA. The general linear model (GLM) was applied to test the differences among the four experimental groups.
Effect of chelated organic zinc amino acids (CH-ZnAA) on growth performance.
1. Average body weight (ABW).
The results were significantly affected at all ages for rabbits received diets containing 300 and 450 mg/kg CH-ZnAA compared with the control diet. The final body weight of treated groups (T2, T3, T4) were highly significant (P<0.001) and higher than the control group (T1) by 5.04, 9.8, and 12.31% respectively. There was no significant difference between treatment groups (T3, T4) in ABW.
2. Body weight gain (BWG).
Results cleared that total body weight gain and average daily gain were highly significant (P<0.01) increased by 7.82, 15.29, and 19.52%, respectively for treated groups (T2, T3, andT4) as compared with the control group. There was no significant difference between treatments T3 and T4 in BWG and ADG.
3. Feed intake (FI).
Total feed intake and average daily feed intake (ADFI) at 6-16 weeks were considerably greater in treated groups (T2, T3, T4) compared to the control group. The percentage of increments achieved were 2.91, 5.33, and 2.85%, respectively. Differences in feed intake among treatments were not significant through 6-8 and 10-12 weeks old.
4. Feed conversion ratio (FCR).
The results observed that the average feed conversion (AFC) throughout the experimental period 6-16 weeks of age was considerably (P< 0.05) affected between treatments. The lowest value 3.29 gm intake/gm body gain was the best for the treatment supplemented with 450 mg CH-ZnAA /kg diet (T4).
5. Digestibility Coefficients:
The data revealed that supplementing rabbit diets with CH-ZnAA resulted in highly significant (P< 0.01) increases in the digestibility of dry matter (DM), organic matter (OM), crude protein (CP), and NFE, as well as significant (P< 0.05) improvements in the digestibility of ether extract (EE), crude fiber (CF), NDF, and hemicellulose compared to unsupplemented diets (control).
6. Carcass characteristics.
The results showed that slaughter weight, hot carcass weight, and hot carcass weight plus total edible organs of rabbits fed supplemented diets were highly significant (P < 0.01) for dressing percentages compared to the control diet. The control group recorded the lowest values, whereas the highest values were found in T4. However, the CH-ZnAA treatment had no appreciable impact on the relative weights of edible organs or the total edible weights.
Effect of chelated organic zinc amino acids (CH-ZnAA) on physiological responses.
1. Blood hematological parameters.
In comparison to the control treatment, CH-ZnAA treatments of rabbits at doses of 300 and 450 mg/kg increased (P < 0.05) RBC count, Hb concentration, and Hct (%). While supplementing of CH-ZnAA at 150 mg/kg had significant (P<0.05) improvement in RBCs count only and failed to show any improvement in Hb concentration and Hct (%) in comparison with the control group. However, erythrocytic values of MCV, MCH, and MCHC were not significantly affected by CH-ZnAA treatment.
2. Blood Biochemical Parameters.
The supplementations of different levels of CH-ZnAA to rabbit diets; improved total protein (TP), albumin (ALB), globulin (Glob), and glucose concentrations. No significant differences were noticed in liver enzymes [aspartate aminotransferase (AST) and alanine aminotransferase (ALT)], kidney functions (creatinine and urea) concentrations, and Thyroid hormones (triiodothyronine and thyroxin) among the studied treatments. The outcomes were improved when we supplemented CH-ZnAA to the rabbits’ diet up to 450 mg/kg which it elevated serum levels of the antioxidants [superoxide dismutase (SOD), glutathione S-transferase (GST), and decreased malondialdehyde (MDA)] concentrations. In conclusion, CH-ZnAA improved the productivity of V-line male rabbits, it is secure and might be advised for use.
Effect of chelated organic zinc amino acids (CH-ZnAA) on economical feature.
The net revenue (NR) was improved by 11.11, 21.95, and 30.82 %, respectively when feeding diets T2, T3, and T4 as compared with T1 (control). The Economic efficiency expressed as (NR/TFC) was increased from 1.35 to 1.70 as T1 was compared with T4, which represents a 25.51% improvement.
CONCLUSION
It was clear from the present study, that supplementation with 150, 300, and 450 mg Zn/kg as CH-ZnAA, which provide 25.50, 51.00, and 76.50 mg Zn/kg DM to V-line male rabbits improved nutrients’ digestibility, growth performance, carcass characteristics, and some blood haematological and biochemical parameters as compared to the control group. The fourth treatment supplementation with 450 mg Zn/kg as CH-ZnAA, which provide 76.50 mg Zn/kg DM was the best among the supplemented treatments. The feed supplementation enhanced the economic efficiency from 1.35 to 1.70 as T1 was compared with T4. finally, CH-ZnAA improved the productivity of V-line male rabbits, and finally it is safe and might be advised to be used in diets of growing rabbits.