الفهرس 
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Abstract
The present work was conducted at the Poultry Research Farm, Faculty of Agriculture, Assiut University. The study had two objectives: the first was to evaluate the nutritive value of corn crunches waste (CCW), potato chips scraps (PCS), potato starchy waste (PSW), and sugar beet pulp (SBP) and the second was to estimate the effect of these wastes and byproducts when used as a dietary partial replacer of yellow corn (at two levels, 5% and 10% of YC) on broilers performance, carcass traits and economic efficiency from 1 day until 42 days of age.
The nutritive value was evaluated by both chemical analysis, gross energy and apparent metabolizable energy calculations. Moreover, to evaluate their effect on the broilers performance. a field experiment was carried out as follows:
A total number of 297 unsexed one-day old ROSS broiler chicks were equally assigned into nine dietary groups (control and 8 treatments), each group of three even replicates. Two levels of each of the four byproducts and wastes partially replaced 5% or 10% of YC in the 8 treatments diets. Body weight (BW), body weight gain (BWG), feed consumption (FC), feed conversion ratio (FCR), and relative economic efficiency (REE) were estimated for the whole experimental period (6 weeks). At the end of the experiment, 6 birds from each group were sacrificed for evaluating different carcass traits.
The results obtained can be summarized as follows:
1. The nutritive value:
1.1. The chemical analysis:
a. The values of crude protein of CCW, PCS, PSW and SBP were 8.60, 8.64, 1.18 and 11.90% (DM); respectively.
b. The values of ether extract was 22.30% for CCW, 37.20% for PCS, 1.41% for PSW and 1.43% for SBP.
c. The values of crude fiber was 2.10% for CCW, 3.33% for PCS, and 27.40% for SBP. while, PSW did not have any fiber.
d. The values of crude ash of CCW, PCS, PSW and SBP were 5.69%, 4.69%, 0.40% and 4.93%; respectively.
e. The values of nitrogen free extract of CCW, PCS, PSW and SBP were 61.30%, 46.10%, 97% and 54.40%; respectively.
Summarizing the above mentioned results, it could be concluded that CCW has low crude protein, crude fibers and ash but has high ether extract and NFE values; however, PCS has low crude protein, crude fibers and ash but high NFE and very high ether extract. Moreover, PSW has low crude protein, very low ether extract and ash, and almost free of crude fibers but very high NFE. Also, SBP has low crude protein, ash, very low ether extract but high NFE and very high crude fibers.
1.2. Energy values:
a. The values of gross energy of CCW, PCS, PSW and SBP were: 5216, 6036, 4233 and 4207 kcal/kg; respectively.
b. The values of apparent metabolizable energy of CCW, PCS, PSW and SBP were 4058, 4438, 3689, and 1101 kcal/kg; respectively.
Based on the above mentioned results, it could say that the four understudy materials have high gross energy. Moreover, they also have high apparent mtabolisable energy except SBP which is due to its low ether extract and high crude fibers contents.
2. Effect of partial substitution of yellow corn with byproducts and wastes on growth performance of broiler chicks:
2.1. Live body weight: The results revealed highly significant differences between treatments (P≤0.01) from the first week of age till 6 weeks of age. It is worthy to mention that the best LBW at 6 weeks of age was proved for the broilers received CCW at 5% of corn; however, the worst LBW at 6 weeks of age was recorded for the broilers received SBP at 5% of yellow corn. Moreover, CCW at 10%, PCS at 5% and PSW at 5% and PSW at 10% of yellow corn did not significantly differ from the control, till the second week of age, but showed unstable trend thereafter.
2.2. Body weight gain: BWG of both CCW at 5% and PCS at 10% of yellow corn did not differ significantly from the control group at all weeks of age. However, BWG of both SBP at 5% followed by SBP at 10% of yellow corn was significantly lower than the controls at all weeks of age. Moreover, CCW at 10%, PCS at 5% and PSW at 5% and PSW at 10% of yellow corn did not significantly differ from the control till the second week of age, but showed unstable trend thereafter.
Based on the data obtained for body weight and body weight gain, it could be concluded that these two criteria did not exhibit any significant differences between the control group and the groups fed CCW at 5% or PCS at 10% of YC at 6 weeks of age.
2.3. Feed consumption: The highest feed consumption was recorded for PSW at 10% of YC in the first and second weeks of age, for PCS at 5% of YC in the third week of age, for CCW at 5% of YC in the fourth and fifth weeks of age, and for SBP at 10% of YC in the sixth week of age.
2.4. Feed conversion ratio: The best FCR was detected for the chicks fed PCS at 5% of YC in the first week of age, and for those fed CCW at 5% of YC in the 2nd, 3rd, 4th and 5th week of age, and for those fed PSW at 5% of YC in the 6th week of age. However, the worst FCR was recorded for the broilers fed SBP at 5% of YC in the 1st, 5th and 6th week of age, for those fed PSW at 5% of YC in 2nd week, for those fed PSW at 10% of YC in 3rd week, and for those fed SBP at 10% of YC in 4th week of age.
Based on the above mentioned results, it could be concluded that there were no significant differences between control group and the other treatments in the overall feed consumption (0-6 weeks of age); however, the overall FCR was significantly worse for the treatments fed PSW at 10% or SBP at 5% or 10% of YC as compared with the control group.
2.5. Mortality: The mortality was within the normal range and was not affected by treatments at different weeks of age or at different pe-riods of growth.
2.6. European broiler index: The better growth performance was de-tected for the control group since it acquired the higher EBI (278). The second order for EBI came for the group fed CCW at 5% of YC (266) and the third order was proved for the group fed PCS at 10% of YC (252). However, the other treatments scored a bad growth performance compared with the control group since their EBI ranged from (217) for PCS at 5% of YC down to (196.9) for SBP at 10% of YC.
3. Effect of partial substitution of yellow corn with byproducts and wastes on slaughter and carcass traits of broiler chicks:
The obtained data proved that the differences between treatments were not significant in regard to percentages of feather, New York car-cass, giblets, inedible viscera, head, shank, neck, eviscerated carcass and dressed carcass. However, there were significant differences between treatments in concern to blood percent, eviscerated carcass weight and dressed carcass weight. It is worthy to mention that in spite of the non significant differences between treatments in regard to eviscerated carcass and dressed carcass percentages; however, they still differed significantly in eviscerated carcass and dressed carcass weights.
The results revealed that the differences between treatments were significant in concern with breast, legs and abdominal fat weights. However, the differences were not significant in respect to percentages of breast and legs, but significant for abdominal fat percentage.
Based on the results obtained, it could be concluded that the broilers received CCW at 5% or those received PCS at 10% of YC did not significantly differ from the control group in different slaughter and carcass criteria specially in weights and percentages of breast and legs (drumstick + thigh).
4. Effect of partial substituting of yellow corn with byproducts and wastes on economic efficiency of broiler chicks:
from our point of view, the economic efficiency in this work could be judged by the compatibility and consistency in the relationships between the three studied criteria: EBI, net revenue and REE. The control group came in the first order in regard to EBI and in the second order in regard to net revenue or relative economic efficiency. The treatment received CCW at 5% of YC came in the first order in regard to net revenue and in the second order in regard to EBI, and in spite of it was in fourth order in regard to REE; however, its REE value was too close to that of the control group (98.86 vs 100%). The treatment received PCS at 10% of YC came in the third order in either EBI, or net revenue and REE. The treatment received PCS at 5% of YC came in the fourth order in EBI and net revenue but in the fifth order in REE. The treatment received PSW at 5% of YC came in the fifth order for EBI; in the sixth order for net revenue but in the first order in REE (very close to the control: 100.11 vs 100%) ; however, this rank may be misleading since it was due to the low feed consumption of this diet.
In general, and based on the results obtained in this study we may come to the following conclusions”
1. Chemical composition: Comparing the evaluated nutritive values of the materials understudy with that of YC, it could be detected that they are all approximately equal to YC in protein percentage except SBP (lower); equal in crude fibers except PSW (almost free) and SBP (much higher); higher in ash percentage except PSW (lower); higher in ether extract except PSW and SBP (lower); equal or higher in NFE except PCS and SBP (lower).
2. Energy values: The four studied byproducts and wastes have higher GE and AME than YC, except SBP which has higher GE but lower AME value.
3. Performance: The broilers fed diets contained CCW at 5% or PCS at 10% of YC were not significantly different from their controls in body weight, body weight gain, feed consumption, feed conversion ratio, and most carcass criteria.
4. Economic efficiency: Usage of CCW at 5% or PCS at 10% of YC still could be competitive to the control group from the economic point of view.
According to the mentioned above conclusions, it could be advised that the partial replacement of YC by 5% CCW or 10% PCS could be of similar nutritive value and competitive economic impact on broiler chicks performance till 6 weeks of age.