الفهرس 
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Abstract
Summary
This study was carried out in Poultry Research Farm, Faculty of Agriculture, Assiut University, Egypt. The experiment was planned in a factorial design (32) to evaluate the stability of the nutritive value of broiler feeds (in specific amino acids lysine and methionine and vitamins) that have been stored for different periods (fresh, 4 months, or 6 months). Therefore, a total number of 450 one-day old unsexed (Hubbard) broiler chicks were randomly distributed into 9 groups, each group of 5 replicates of 10 chicks each (n = 50/group). The groups were as follows: G1 (fresh basal diet + no dietary supplements), G2 (fresh basal diet + methionine at a level of 5g/ kg feed + lysine at a level of 13 g/ kg feed) (Starter) and (basal diet + methionine at a level of 4g/ kg feed + lysine at a level of 10g/ kg feed) (Grower), G3 (fresh basal diet + vit. premix at a level of 3 kg per ton), G4 (basal diet stored for 4 months + no dietary supplements), G5 (basal diet stored for 4 months + methionine at a level of 5g/ kg feed + lysine at a level of 13 g/ kg feed) (Starter) and (basal diet + methionine at a level of 4g/ kg feed + lysine at a level of 10g/ kg feed) (Grower), G6 (basal diet stored for 4 months + vit. premix at a level of 3 kg per ton), G7 (basal diet stored for 6 months + no dietary supplements), G8 (basal diet stored for 6 months + methionine at a level of 5g/ kg feed + lysine at a level of 13 g/ kg feed) (Starter) and (basal diet + methionine at a level of 4g/ kg feed + lysine at a level of 10g/ kg feed) (Grower), G9 (basal diet stored for 6 months + vit. premix at a level of 3 kg per ton).
The experiment prolonged for 6 weeks (from 0 to 42 days of age). Chicks were fed a starter diet from 0 to 3 and a grower diet from 4 to 6 weeks of age
The experiment revealed the following results:
1. Live body weight
The groups received feed that has been stored for 4 or 6 months and enriched with double level of amino acids (lysine and methionine) (G5, G8) had significantly heavier LBW from age of 4 weeks to age of 6 weeks compared to the control group (G1).
2. Body weight gain
The effect of storage period and dietary treatment on body weight gain was similar to their effect on LBW the birds received feed supplemented with double level of lysine and methionine and was stored for 4 months or 6 months had significantly heavier BWG during the overall period (0 - 6 weeks) compared to the control group.
3. Feed consumption (FC)
The birds received double level of amino acids (T2) recorded significant increase in feed consumption during the overall period (0 - 6 weeks) compared with the other dietary treatments.
4. Feed conversion ratio (FCR)
In respect to feed conversion ratio for the overall period (0 – 6 weeks), the results revealed significant improvement in FCR for the group received feed stored for 4 months and enriched with double level of amino acids (lysine and methionine) (G5).
5. Mortality
During the experiment, only 4 cases of mortality occurred, and each of these cases was in a different group. In general, no impact was proved for feed storage period or dietary treatment on mortality rate.
6. Carcass traits
Eviscerated carcass and dressed carcass percentages tended to be higher in the groups received double level of amino acid (lysine and methionine) regardless of the storage period. Moreover, abdominal fat % was less in all groups that received double level of amino acid as compared to the control group. Besides, spleen and bursa percentages were higher in the groups received double dose of vitamin premix.
7. Blood haematological parameters
Haemoglobin was significantly higher in blood of the birds received double level of vitamins premix. Moreover, lymphocyte was significantly higher in blood of the control group. However, heterophils and Monocyte were significantly higher in blood of the birds that received double level of amino acids (lysine and methionine). The H/L ratio was higher in all groups received double dose of amino acids specially G8 (6 months + amino acids).
8 . Blood proteins
Blood plasma albumin and globulin proteins were not affected by storage period or dietary treatment; however, total protein was significantly higher in blood plasma of the birds received double level of the vitamins premix.
9. Economic efficiency
The relative economic efficiency was better for all groups that received double dose of amino acids (specially G5) compared to the control group (G1).
10. Aflatoxins
Storage period did not have any significant effect on B1, B2, G1 and G2 aflatoxins counts may be due to the presence of antioxidants supplement.
5.2. Conclusions
According to the overall results summarized in Table 18, it could be concluded that:
1. It has been proven that body weight, body weight gain, feed consumption, and feed conversion ratio were not adversely affected by storing broiler feeds for different periods (4 months, and 6 months).
2. It was revealed that enrichment of broiler diets that has been stored for 4 to 6 months with double level of NRC for lysine and methionine (methionine at a level of 5g/kg feed + lysine at a level of 13g/kg feed) (starter) (methionine at a level of 4g/ kg feed + lysine at a level of 10g/ kg feed) (Grower) from the first day to the 42nd day of age had beneficial effects on final body weight gain, FC, FCR (0-6 weeks), increased percentages of eviscerated carcass and dressed carcass, and decreased abdominal fat. Moreover, it improved the weight of bursa and spleen, and increased Monocyte, heterophil and H/L ratio, haemoglobin, globulins and total plasma proteins. Also, it increased the relative economic efficiency.
3. Supplementing broiler diets that have been stored for 4-6 months with higher dose of vitamin premix (double level of NRC) in presence of antioxidants revealed a slight or insignificant difference from fresh diets on the different studied criteria.
4. Based on the results of the present study, it could be concluded that: under Egyptian circumstances, enrichment of broiler feeds with higher levels of lysine and methionine (double level of NRC) together with antioxidants supplement could prolong their shelf-life to 6 months without any deleterious impact on productive performance or economic efficiency of