• Asian-Australasian Journal of Animal Sciences
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• v.15 no.9
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• pp.1319-1325
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• 2002

Two experiments were conducted to evaluate the effect of early feed restriction on growth, feed conversion ratio (FCR) and mortality in unsexed broiler chickens. In Experiment 1, 350 one-day-old broiler chickens were divided into 7 groups. Each treatment group was represented by five replicates of ten broilers each. One group was fed ad libitum as the control group and the other six groups were fed 25% ad libitum (25% multiplied by amount of feed intake of ad libitum chickens at the previous day) for 4 or 6 days, 50% ad libitum for 4 or 6 days, and 75% ad libitum for 4 or 6 days. In experiment 2, 500 broiler chickens were divided into 10 groups. Each treatment group was represented by five replicates of ten broilers each. One group was fed ad libitum as the control group. Three ages of feed restriction initial timing (2, 4 or 6 days of age) and three types of feed restriction (physical restriction, meal feeding and diet dilution) were used ($3{\times}3$) in both experiments. They were feed-restricted for 6 days. Results showed that restricted broilers exhibited compensatory growth in both experiments except for diet dilution groups. In both experiments, FCR of restricted broilers was higher, whereas feed intake of them was lower during restriction period. FCR of restricted broilers was lower upon refeeding. Mortality was inconsistently affected by early feed restriction. Leg abnormality was lower in restricted broilers in both experiments. Level of feed restriction significantly influenced body weight, FCR and feed intake of restricted broilers (p<0.05), but duration of feed restriction had no effect. Type of restriction significantly affected body weight, feed intake and FCR (p<0.05). It appeared that to achieve the best result (complete compensatory growth and better FCR), broilers should be restricted at 25% ad libitum for 6 days (Experiment 1). Meal feeding started at 2 days of age would show the best performance (Experiment 2).

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.1
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• pp.63-67
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• 1996

An experiment was conducted to compare the effects of early feed restriction on the performance and abdominal fat deposition in broilers. The treatments consisted of providing feed ad libitum (Full-fed) and three feed restriction treatments of restricting feeding between 8-21 days of age (DOA) either for a duration of 7 days or 14 days. The three feed restriction treatments were Restrict 8-14 DOA, Restrict 8-21 DOA and Restrict 15-21 DOA. Live weights and feed consumption were obtained at weekly intervals. Samples of both male and female broilers were taken at 43 DOA to determine the weight of abdominal fat, liver and gizzards. Feed efficiency was generally improved by feed restriction, but a compensatory gain was not observed in the restricted groups. Broilers on restricted feeding also had lower mortality as compared to the full-fed broilers. There is no effect of early feed restriction on the weight of the abdominal fat and the dressing percentages but the weights of the liver and gizzard were affected by restriction. Also there was an effect of sex on the weights of the abdominal fat, the liver and gizzard of the males and females.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2001.11a
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• pp.99-101
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• 2001

Three experiments were conducted with broilers to study the effects of early feed restriction. In all studies, treatments were represented by three replicated floor pens, each containing 20 birds. In Experiment 1, broilers were fed at 0.75 kcal ME/g BW/sup0.67 for 3 d, 1.5kcal m/E BW/sup0.67 for 5 d or 2.25 kcal ME/g BW/sup0.67 for 7 d, all imposed beginning at 7 d of age. Birds were smaller following feed restriction(P<0.05), although growth compensation occurred, and at 49 d all restricted birds were same(P>0.05) to full-fed control buds in body weight. Growth compensation was associated with improved feed conversion(P<0.05), although carcass composition was unchanged. In a second study, all birds were fed at 0.75 kcal ME/g BW/sup0.67 for 3 or 5 d, starting at either 4, 7, or 10 d of age. When feed restriction was applied for shorter periods of time, growth compensation occurred(P>0.05). With more severe feed restriction, birds were smaller(P<0.05) at 49 d compared to control. Feed conversion was improved following prior feed restriction(P<0.05, 4 to 49). In a third trial, broilers were fed a starter diet diluted with 50% rice hulls. Birds failed to consume enough of this diluted feed, and so were initially smaller, However 49 d weight was not affected (P>0.05). When periods of 24 h feed withdrawal were imposed in conjunction with the diluted diets, birds were under weight at 49 d. It is concluded that physical feed restriction at 0.75 to 1.5 kcal ME/g BW$\^$0.67 imposed for 3 to 5 d in the early life currently presents the best option as a means of controlling broiler growth so as to improve feed efficiency.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.10
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• pp.1475-1481
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• 2002

The study was conducted to evaluate the effect of early feed restriction on growth, fat accumulation and meat composition in unsexed broiler chickens. In experiment 1, three hundred and fifty one-day-old broiler chicks were divided into 7 groups. Each treatment group was represented by five replicates of ten broilers each. One group was fed ad libitum as the control group and the other six groups were fed 25% ad libitum (25% multiplied by amount of feed intake of ad libitum chicks at the previous day) for 4 or 6 days, 50% ad libitum for 4 or 6 days, and 75% ad libitum for 4 or 6 days. In experiment 2, five hundred broiler chicks were divided into 10 groups. Each treatment group was represented by five replicates of ten broilers each. One group was fed ad libitum as the control group. Three initial age at which broilers were restricted (2, 4 or 6 days of age) and three type of feed restriction (physical restriction, meal feeding and diet dilution) ($3{\times}3$) were examined. They were restricted feeding for 6 days. Experimental results showed that broilers fed 25% ad libitum for 4-6 days tended to reduce leg meat fat with lower abdominal fat (p<0.05) (experiment 1). Breast meat fat was significantly higher in restricted broilers (p<0.01). Plasma triglyceride was higher in broilers fed 75% ad libitum for 4-6 days. In experiment 2, abdominal fat was lower in restricted broilers (p<0.05). Breast meat fat was significantly higher (p<0.01), whereas leg meat fat was significantly lower (p<0.05) in restricted broilers. Plasma triglyceride was significantly higher in physical feed restriction for 4 days, meal feeding for 4 days and diet dilution for 6 days (p<0.05). In conclusion, to reduce fat accumulation in abdomen and leg meat, broilers should be fed 25% ad libitum for 6 days started at 4 days, or subjected to meal feeding (6 hours per day for 6 days) started at 6 days.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.11
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• pp.1585-1591
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• 2001

The present study was conducted to evaluate the effect of early feed restriction on growth, fat accumulation and meat composition in unsexed broiler chickens. Five hundred 7-day old unsexed broiler chickens were distributed into ten treatment groups with 5 pens of 10 broilers each group. One group was fed ad libitum as the control group and other nine groups were fed 25% ad libitum for 3, 6 or 9 days, 50% ad libitum for 3, 6 or 9 days, and 75% ad libitum for 3, 6 or 9 days, respectively. Thereafter, they were fed ad libitum to 56 days of age. The present results showed that broilers showed compensatory growth when they were restrict-refed. Feed conversion ratio was significantly lower in broilers fed 25% ad libitum for 9 days (p<0.05). Triglyceride concentration of serum was significantly lower in restricted unsexed broilers (p <0.01), whereas cholesterol concentration was not significantly different. Abdominal fat was significantly lower in broilers fed 25% ad libitum for 9 days, 50% ad libitum for 3 days and 75% ad libitum for 6 or 9 days (p<0.05). Moisture and protein contents of meats were not significantly affected. Ash content of meat was significantly higher in restricted broilers. Fat content of meat was lower in broilers fed 25% ad libitum for 9 days, 75% ad libitum for 3 to 9 days. In conclusion, broilers showed compensatory growth when they were restrict-refed at an early age. In order to achieve the success of early feed restriction (namely reduce fat accumulation and improve feed conversion ratio with comparable body weight at market age), unsexed broilers should be fed at level of 25 ad libi=tum for 9 days starting at 7 days of age.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.3
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• pp.451-461
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• 1993

Four hundred and eighty broiler chicks of both sexes were obtained from commercial hatchery (Hubbard) and raised on floor pens. All chicks were allowed free access to food from 0 to 7 and 20 to 56 days of age. At 7 days of age, all broilers were weighed individually, and divided into five groups as follows: 1. feed ad libitum as the control; 2. allowed free access to food 3 days and starved 1 day ($3{\times}1$); 3. allowed free access to food 2 days and starved 1 day ($2{\times}1$); 4. allowed free access to food 1 day and starved 1 days ($1{\times}1$) and; 5. allowed free access to food 2 days and starved 2 days ($2{\times}2$). Broilers were restricted for 12 days (d 7 through 17) of a 56-day trial. Broilers were fed a commercial starter diet (crude protein 23.8% and ME 3,070 kcal/kg) for 21 days, and commercial finisher diet (crude protein 20% and ME 3,160 kcal/kg) from 22 to 56 days of age. Although there was compensatory growth in some groups, (the $1{\times}1$ female group, and the $3{\times}1$ and $2{\times}1$ male grous), its level was not sufficient to achieve normal body weight at market age. There was sexual dimorphism for accelerated growth as well as differences in the ability to achieve a complete compensation of growth to the weight, feed conversion ratio, and body composition of ad libitum chicks. Early feed restriction could be used to reduce production cost because of the lower fed conversion ratio, mortality rate and the amount of starter diet consumed by broilers. The response of chicks to early feed restriction might depend on the degree of feed restriction, the method of feed restriction, duration of feed restriction, and sexes.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.3
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• pp.401-410
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• 1993

Day-old male and female broilers obtained from commercial strain (Hubbard) were used in this study. At 7 days of age, all chicks were weighed individually (female 0.11 kg and male 0.12 kg in average) and divided into 5 group of 45 birds each group with no replicate in each treatment group as follows: 1. fed ad libitum; 2. fed 75% ad libitum; 3. fed 65% ad libitum; 4. fed 55% ad libitum; 5. fed 45% ad libitum. Chicks were restricted for 10 days (d 7 through 17) of a 56-day trial. Chicks were fed a commercial starter diet (crude protein (CP) 23.8% and metabolizable energy (ME) 3,070 kcal/kg) for 21 days, and commercial finisher diet (CP 20% and ME 3,160 kcal/kg) from 22 to 56 days of age. When chicks were feed-restricted at an early age, compensatory growth did not immediately occur following refeeding. Body weights of restricted chicks were not equal to the ad libitum chicks before 49 days of age. At 56 dyas of age, body weights of restricted chicks were heavier (p<0.01). Abdominal fat values of female chicks fed ad libitum was not significantly different from those fed 45% to 75% ad libitum. Carcass fat values of restricted female chicks were lower than those of control chicks when female chicks were fed either 55% or 45% ad libitum. Furthermore, feed efficiencies of restricted chicks were better. The response of chicks to early feed restriction might depend on the degree of feed restriction, and sex. Factors contributing carcass fat included energy loss, fat protein ratio of carcass, fatty acid synthesis in the liver and triglyceride content of the liver. The heavier body weights in the restricted chicks might be correlated with the lower growth rate during period of feed restriction.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.11
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• pp.1581-1586
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• 2009

The present study was conducted to determine the effects of two types of housing systems and early age feed restriction on stress and fear reactions, and performance in broiler chickens raised in a hot, humid tropical climate. On day 1, chicks were housed either in windowless environmentally controlled chambers (temperature was set at 32$^{\circ}C$ on day 1 and gradually reduced to 23$^{\circ}C$ by day 21) or in conventional open-sided houses (OH) with cyclic temperatures (minimum, 24$^{\circ}C$; maximum, 34$^{\circ}C$). An equal number of chicks from each housing system was subjected to either ad libitum feeding (AL) or 60% feed restriction on day 4, 5 and 6 (FR). The CH birds showed greater weight gain, higher feed consumption and better feed conversion ratios (FCR) than their OH counterparts. Feeding regimen had negligible effect on overall performance. Neither housing nor feeding regimen had a significant (p<0.05) effect on mortality rate. Although the CH birds were less stressed, as measured by plasma corticosterone concentration (CORT), than those of OH, the former showed longer TI duration suggesting higher magnitude of underlying fearfulness. A significant (p<0.05) effect of housing on heterophil/lymphocyte ratios was only noted among the AL birds where the CH birds had higher values than OH. Collectively, these results suggest that although OH birds had poorer performance and higher level of stress than CH, the former were less fearful. Although FR had negligible effect on growth performance, the regimen alleviated both stress and fear reactions in broilers.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2003.11a
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• pp.117-118
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• 2003

This experiment was conducted to investigate the effect of feed restriction in early stage of growth on the compensatory growth in male and female broiler chickens. Day-old 480 male and 480 female commercial broiler chickens(Ross strain) were randomly allotted to 32 pens(replicates), 30 birds per pen, to compare the sex difference in growth performance and carcass characteristics. Birds in control group(C) were full fed throughout the study. T1, T2 and T3 were restricted at 4∼11d, 4∼14d and 4∼18d, respectively. Chickens were weighed every week, and one bird was selected from each pen to measure carcass characteristics at the end of experiment. In female chickens, all restricted-fed groups except for T3 weighed same as or heavier than the control group at 7 weeks of age. In male chickens, both T2 and T3 that had longer feed restriction period were significantly different from the control group. Viability was not different significantly. Feed intake in both male and female chickens of T3 group statistically differed from the control group. The female chicks showed larger abdominal fat pad sizes than did male birds up to market age.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.6
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• pp.657-664
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• 1997

432 Babcock ISA white leghorn pullets reared for 8 weeks on a standard managemental conditions were exposed to feed/nutrient and light restrictions from 9 to 20 weeks of age. Four feeding regimes i. e. 100, 85 or 70 percent of the recommended allowance and low energy (2,500 Kcal/kg) low protein (13% CP) ration were fed each in the three light regimes i. e. (A) Natural day light starting from 13.24 hr/day at 8 weeks of age and ending 10.41 hr/day at the end of 20 weeks; (B) Constant 11 hr/day light and (C) starting with 13 hr/day at 8 weeks and decreasing @ 20 min/week till 20 weeks of age. At the age of 20 weeks all the birds were shifted to separate cages under uniform lighting feeding and management. During the 21st week light was increased to 12 hr a day and thereafter with an increase of 30 min per week, increased to 16 hr a day at the age of 29 weeks. From 20 weeks onward till 72 week age, all the birds were offered commercial layer rations ad libitum, prepared according to climatic conditions. The results of the study revealed that birds reared under natural and constant light had higher weights than decreasing light, yet they could not out perform during production period. The effect of feed and nutrient restriction, on the other hand, was found significant during rearing as well as production period. The birds exposed to higher level of feed and those exposed to nutrient restriction were lighter in weight. The 100% fed birds laid their first egg at an early age. However, those reared on 85% of the recommendation excelled all other groups in terms of produced number of eggs, egg mass, hen housed and hen day production and net returns.