Hasan Rüştü Kutlu

Changes in growth and blood parameters in heat-stressed broiler chicks in response to dietary ascorbic acid

Abstract Three experiments were conducted to determine whether supplemental ascorbic acid (AA) would alleviate heat-induced deterioration in performance and metabolism of broiler chicks. Day-old female broiler chicks were fed ad lib. on a standard starter feed under either thermoneutral (UH) or heated (H, thermoneutral, heated to 36°C for 6–10 hours per day) conditions to 4 weeks of age. In Experiments 1 and 3 the diet was supplemented with 0, 250, 500 or 1000 mg/kg AA. In Experiment 2, AA was given at 200 mg/kg. In Experiment 1, which started at 7 days of age, heating significantly reduced body growth, feed intake and feed efficiency. AA supplementation, particularly at 250 mg/kg, stimulated growth, intake and efficiency in the H birds but had no significant effect under UH conditions. At both temperatures AA supplementation increased adrenal weight and plasma AA concentration at the end of the experiment. Heating depressed growth, intake, efficiency and adrenal weight in Experiment 2, starting at 1 day of age, while plasma AA levels were increased. AA supplementation increased growth, intake and efficiency of H birds while having no effect under UH conditions. In the third Experiment, starting at 7 days of age, heating reduced growth, intake, efficiency, thyroid weight, and levels of plasma protein, potassium and calcium while increasing body temperature, water intake and plasma glucose, cholesterol and sodium. Under H conditions, AA supplementation alleviated many of these effects, particularly when included at 250 mg/kg. No significant influence was associated with AA supplementation under UH conditions. These data demonstrate that AA, particularly at 250 mg/kg, ameliorates the heat-induced deterioration in performance and metabolism of broiler chicks. AA supplementation of non-heat-stressed birds tends to reduce performance.

Self-selection of ascorbic acid in coloured foods by heat-stressed broiler chicks

Female broiler chicks were given red and green supplemented (200 mg ascorbic acid (AA)/kg) and unsupplemented foods on alternate days for 8 days under heat-stressed and unstressed conditions. After this training period, the birds were given access to both foods, and the intake of each was monitored. In both heated treatments the intake of the supplemented food was significantly higher (p < 0.05) than of the unsupplemented food (800 vs. 518 g/14 days), although in the unheated groups significantly more of the unsupplemented food was eaten (756 vs. 639 g/14 days). Birds were unable to select for AA when neither food was coloured, even when they were presented continuously in the same positions in the cage. It is concluded that chicks can learn to associate the colour of the food with its AA content and that they select proportions of supplemented and unsupplemented foods appropriate for their needs, as influenced by environmental temperature.

Nutritional consequences among ingredients of free-choice feeding Awassi lambs

Abstract The present study was designed (1) to test whether growing lambs can select an adequate diet when offered an unrestricted choice among feed ingredients, and (2) to determine whether choice feeding compared with single-feeding would alter the fattening performance of lambs reared under normal husbandry conditions. Thirty, 3-month-old male Awassi lambs were used. Each dietary treatment had three replicate groups, comprising five lambs each. Ground barley, wheat bran, cottonseed meal and alfalfa hay were used as the main feed ingredients. One of the dietary treatments (choice-fed) was offering the main feed ingredients as choices, while the other (single-fed) was feeding with a control diet (containing 2.4 Mcal ME kg−1 and 17.0% CP) prepared using the same feed ingredients for a 56 day fattening period. Lambs offered choices among the feed ingredients could select diets to meet their nutrient requirements according to age throughout the fattening period. For the entire experimental period the choice-fed group attained higher daily live-weight gain (346 g vs. 299 g; P 0.05) between daily feed intake of the choice-fed and single-fed groups (1776 g vs. 1704 g) was observed. The lambs consistently selected diets high in CP relative to ME when allowed to choose feed ingredients. It is concluded that lambs, when given choices among feed ingredients (ground barley, cotton seed meal, wheat bran and alfalfa straw), can select diets that meet their nutrient requirements according to stage of maturity and they attain better growth performance than lambs fed with a single diet.

Effects of Dietary Yucca schidigera Powder on Performance and Egg Cholesterol Content of Laying Hens

Abstract Kutlu, H.R., Görgülü, M. and Ünsal, I. 2001 Effects of dietary Yucca schidigera powder on performance and egg cholesterol content of laying hens. J. Appl. Anim. Res., 20: 49–56. The present study was carried out to determine whether dietary Yucca schidigera powder would affect egg yolk cholesterol content and laying performance of chickens. Sixty, 28-week-old White Hyline layers were divided into four dietary treatment groups of similar mean weight, comprising 15 birds each. A standard layer feed as the basal diet of the trial was supplemented with 0, 30, 60 or l20 ppm Yucca schidigera powder. Yucca supplementation to the diet did not affect feed intake, egg production, feed conversion efficiency, body weight gain, egg shell, white and yolk weights, shell thickness and shape index but reduced number of cracked eggs (P<0.05). Yucca supplementation also reduced yolk cholesterol content in a dose related (P<0.05) and a time dependent (P<0.01) manner.