A total of 120 Tilapia nilotica fingerlings were fed diets supplemented with 0, 5000, 10 000 and 40 000 IU vitamin A k -' diet, respectively, at a rate of 3% of body weight for 18 weeks. The Vitamin A unsupplementef grou developed severe signs of vitamin deficiencies (restlessness, abnormal movement, blindness, exop%thalmia, haemorrhages of eyes, fins and skin, pot-belly syndrome, reduced mucous secretion). Growth and feed consumption were severely depressed, and the mortality rate amounted to 48%. An addition of 5000,lO 000 and 40 000 IU vitamin A resulted in a body weight gain of 23.9, 21.6 and 13.2 g, a feed consumption of 60.2, 59.6 and 50.2 g, a feed/gain ratio of 2.5, 2.8 and 3.8 /g and mortality rates of 7%, 7% and 33%, res ectively. Clinical signs and ost mortem lesions of ingerlings with hy ervitaminosis were impaireJ skeletal formation, especia8y i f the vertebrae, haemorrhages of the siin, necrosis of the caudal fin and enlargement of the liver and sfleen. 1t.k concluded that 5000 IU vitamin A kg-' diet covers the re uirement of Tilapia nilotica finger ings, while 10 000 IU already show signs of metabolic distortion an1 even higher dosages cause hypervitaminosis.

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The current study was conducted to investigate the effect of graded levels of betaine supplementation to the normal and low energy diets of broiler chickens during summer season on growth performance, tonic immobility (TI), economic value and some blood biochemical parameters. Three hundred one days-old broiler chicks were used. The chicks were divided into 6 groups (each of 50 chicks) and each group was 5 replicated (2x3 factorial design). The first, second and third groups were fed normal energy diet (NED) with 0, 1 and 2g betaine/kg diet (air dry basis) for 35 days, respectively. While, the fourth, fifth and sixth groups were fed low energy diet (LED) with 0, 1 and 2 g betaine/kg diet (air dry basis) for 35 days, respectively. The experiment was carried out during summer season. Birds freely access to water and feed. Results showed no significant difference of growth performance between NED and LED groups. Betaine supplementation (2g/kg diet) to both NED and LED increased significantly (p<0.05) the body weight (BW) (1880.61 and 1787.66g, respectively), body weight gain (BWG) (1822.22 and 1728.77g, respectively), feed intake (FI) (3027.36 and 3136.42g, respectively), relative growth rate (RGR) (187.93 and 187.24, respectively) and TI (92.83 and 71.83s, respectively) with no significant difference in feed conversion (FCR) between the groups fed diet supplemented with or without betaine. Betaine supplementation 2g/kg diet to NED increased the total cost, total return, net profit, economic efficiency and performance index%, moreover improved the pancreatic and thyroid function and return the lipids indices of LED-fed birds to the normal level as in the NED-fed birds. No mortalities occur between the different groups. Therefore, betaine can be included in normal energy diets of broiler chickens by level of 2g/kg diet for improving the growth performance, economic value and welfare during the summer season.

An experiment was designed to investigate the influence of different levels of dietary inclusion of sunflower meal on broiler's productive performance, serum lipid profile, carcass traits, litter moisture and economic efficiency. One hundred and twenty, day-old Cobb broiler chicks were assigned randomly into 5 equal groups, each contained 24 chicks in three replicate pens (8 chicks/pen). Group 1 was fed on basal diet without sunflower meal and kept as a control group, while groups from 2 to 5 were fed on diets contained 2.5, 5, 7.5 and 10% sunflower meal, respectively. Birds individual weights and pen feed consumed were determined for each feeding period for determining the average body weight (BW), average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR). At the trial end, a total of six birds from each group were picked randomly, slaughtered and the visceral organs (liver, gizzard, heart and spleen) plus fat pad were separately weighed for calculating the dressing percentage and the percentage of internal organs relative to carcass weight. Furthermore, litter moisture percentage and economic efficiency were calculated at the trial end. The averages of BW, ADG, ADFI and FCR were not significantly differed among groups. No differences (P>0.05) were observed in the serum lipid parameters and carcass traits among experimental groups. However, the spleen percentage was significantly higher in broilers group that fed on 10% sunflower meal in comparison to those fed on 2.5, 5 and 7.5 sunflower meal, while the litter moisture percentage was not significantly affected. The best economic efficiency was reported in broilers group fed on 10% sunflower meal but the difference did not reach the significance level. It is concluded that levels up to 10% of sunflower meal can be successfully incorporated in broiler chicken diets.

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