Abdominal Fat Of Broilers Research Articles

Pengaruh kepadatan kandang dan pembatasan ransum terhadap performans produksi dan tingkat cekaman pada Ayam Broiler

This study aims to determine the interaction between cage density with dietary restrictions on ration consumption, growth, feed conversion, carcass percentage, abdominal fat, heterophile-lymphocyte ratio and broiler chicken's Income Over Feed Cost. The research lasted for 2 months in the Cage of Broiler Chicken Farm SMK Negeri I Nabire. The research material used was 135 DOC unsex Cobb strain (CP 707) with an average weight of 42.5 grams / head; commercial feed starter BR1 CP 511 B and finisher BR2 CP 512 B and 27 units of battery cages. The experimental design used was a completely randomized design factorial pattern (3 x 3). Factor I is enclosure density with 3 levels, namely K1 (3 animals / 0.5 m2), K2 (5 animals / 0.5 m2) and K3 (7 animals / 0.5 m2) and Factor II is restriction on ration with 3 levels namely R1 (100% according to ad libitum requirements), R2 (85%) and R3 (70%) given at 4-5 weeks of age. Each treatment combination was repeated 3 times to obtain 27 experimental unit units. The results showed there was no interaction between cage density factors with dietary limitation factors for all observational variables. But the cage density factor, significantly (P <0.05) shows that the denser the cage the lower the consumption of rations and the percentage of abdominal fat in broilers. Whereas the restriction factor of the ration, significantly (P <0.05) indicates that the higher the percentage of restriction ration the lower the ration consumed and the higher Income Over Feed Cost (the greater the business income of broiler chickens obtained) despite the indication of stress in broilers with a high average heterophyll-lymphocyte (H / L) ratio of 2.44.

Addition Of Coleus Amboinicus, L Leaf’s Extract In Ration To Percentage Of Carcass, Abdominal Fat, Liver And Heart Broiler

The purpose of this study was to determine the effect of giving coleus amboinicus, L leaf’s extract, on the percentage of carcass, liver, heart and abdominal fat and the level of coleus amboinicus,L extract which is appropriate in broiler feed. This research was conducted in labor and broiler enclosures of the Payakumbuh State Agricultural Polytechnic, from January to May 2018. The material was DOC, commercial food 311, corn, bran, soybean meal, fish meal and minerals, and the equipment used was cages and equipment. The design used is RAL with 6 treatments and 4 replications. The results obtained that the addition of coleus amboinicus, L extract, L did not affect significantly (P> 0.05) on the percentage of carcass and liver, while the administration of coleus amboinicus, L leaf’s extract significantly affected (P <0.05) on the percentage of heart and abdominal fat broiler. Giving a dry of coleus amboinicus leaf’s, L, 4 g / kg ration can reduce broiler abdominal fat.

Effectivity of liquid herbal and supplemented frequency on the body weight percentage of the carcass and abdominal fat of broilers

The study was conducted to determine the effectiveness of two liquid herbals and interval regulation on the percentage of the carcass and abdominal fat of broilers. The experiment was carried out in a completely randomized factorial pattern design with factor A (combination of herbal ingredients) factor B (when giving herbal ingredients) in 4 replications. Liquid herbals supplemented to broilers consist of 5 herbal ingredients(A1) and consist of7 herbal ingredients (A2) that supplemented to broilers every day (B1) and every 2 days (B2). Measured Parameters were body weight, the percentage of the carcass and abdominal fat. Analysis of variances showed liquid herbals and interval regulation added in water did not have a significant effect (P> 0.05) on the percentage of carcasses and body weight even though the average rate showed a trend of improvement but a significant effect on the percentage of abdominal fat based on LSD test results.

157 ValiMP, a mixture of phytogenic compounds with manganese, reduces abdominal fat in broilers.

157 ValiMP, a mixture of phytogenic compounds with manganese, reduces abdominal fat in broilers.

Comparative analysis of differentially expressed genes related to triglyceride metabolism between intramuscular fat and abdominal fat in broilers

ABSTRACT1. Lipid metabolism is an indispensable process in an organism, though little is known about the regulatory mechanisms of fat deposition in different types of adipose tissues.2. The differentially expressed genes related to triglyceride (TG) metabolism between abdominal and intramuscular fat (IMF) of Beijing-You chickens were investigated in this study.3. TG content in abdominal fat (AF) (349.7 mg/g) was significantly higher (P < 0.01) than in the breast and thigh (12.3 mg/g and 24.8 mg/g, respectively).4. Using Agilent chicken gene-expression profiling in adipose tissues between AF and muscle (breast and thigh), certain representative genes related to fatty acid metabolism, lipoprotein catabolism and esterification reactions were significantly upregulated (P < 0.05 or P < 0.01).5. Genes involved in fatty acid oxidation or carbohydrate utilisation were significantly up- or downregulated (P < 0.05 or P < 0.01), including those involved with highly enriched pathways of lipid metabolism (PPAR, Wnt pathway and inositol phosphate metabolism), cell junctions (focal adhesion and regulation of actin cytoskeleton) and muscle contraction.6. Overall, higher TG levels were observed in AF tissue than in adipose tissues of breast and thigh, which could be regulated through gene expression of pathways related to lipid metabolism (PPAR, Wnt pathway and inositol phosphate metabolism), cell junctions (focal adhesion and regulation of actin cytoskeleton) and muscle contraction. These results provide clues to understanding the molecular mechanisms of TG metabolism between abdominal and IMF.

Moringa leaf meal as natural feed additives on the growth performance and meat quality of commercial broiler chicken

A study was conducted to investigate the effect of dietary moringa leaf meal (MLM) as a natural alternative to antibiotic on the growth performance, meat quality and carcass yield of broiler chicken. A total of 270 day-old broiler chicks were randomly weighed and assigned to six dietary treatments having 45 birds in each. Each dietary treatment had three replicates of 15 birds and was reared in floor pens. Chicks were distributed in 4 different inclusion levels of MLM in diets; 0.5%, 1.0%, 1.5% and 2.0% with 2 control diets negative and positive. The birds were fed the experimental diets and water was provided without restriction throughout the experimental period. The results showed that significant (P&lt;0.05) effect on final body weight and weight gain in dietary supplementation of 1.5% MLM as compared to that of control group. Better feed conversion (1.53) was observed at 1.5% MLM group. Different levels of MLM exhibit significant influence on meat yield performance of broilers. There was no significant difference (P&gt;0.05) observed among the average live weight, thigh meat, wing meat, drumstick meat, gizzard and abdominal fat of broilers. Breast meat, heart, liver, large intestine and dressing percentage showed significant difference. Lower mortality was found on diet supplemented with MLM. It is concluded that 1.5% MLM in broiler diets can be used as natural feed additive for enhancing growth performance, organ development, meat yield and serum cholesterol of broilers as well as replacing of oxytetracycline.Asian J. Med. Biol. Res. June 2017, 3(2): 240-244

KUALITAS KARKAS AYAM PEDAGING YANG DIBERI RANSUM MENGANDUNG LIMBAH SAWI

ABSTRACT CARCASS QUALITY OF BROILERS FED RATION CONTAINING WASTE OF SAWI. Study was conducted to evaluate the effect of substituting part of ration with sawi waste meal on carcass quality and abdominal fat of broilers. Total of sixty unsexed day old chick broilers of MB-202 P strain were randomly divided into twenty units of pens, each of pen was filled with three heads of chicks. Birds were maintained during forty days. Levels of substituting part of ration with sawi waste meal were 0, 5, 10, 15, and 20 percents. Each treatment had four replications using completely randomized design with 5 x 4. Fresh water and ration were given ad libitum. Birds from day old chick to the age of twenty one days old were fed with BR-21E ration for all treatments. The treatments of ration were fed at ages of twenty two days old to the end of study (period when all animals were slaughtered). Data were analyzed using F test and Tukey test for the significant F test. Results showed that control treatments were significantly different (P&lt;0.05) with those others four treatments for carcass weight, but not significantly different with those others four treatments for carcass percentages and abdominal fat. Therefore, sawi waste meal can be used to substitute part of ration up to 20 percents for broilers ration in term of the carcass percentages and abdominal fat. Key words: Sawi waste meal, broilers, carcass quality.

PENGARUH PEMBERIAN EKSTRAK DAUN BANDOTAN (Ageratum Conyzoides) TERHADAP BERAT KARKAS DAN LEMAK ABDOMINAL AYAM BROILER (Effect of Ageratum conyzoides Leaf Extract Administration on Carcass Weight and Abdominal Fat of Broilers)

This study was aimed to determine effect of bandotan (Ageratum conyzoides) leaf extract on the carcass weight and abdominal fat of broiler. A total of 15 chicken with the age of twenty five days old were used in this study and allotted into 3 groups with 5 chickens per groups. Broiler in group P0 (as a control) were not given bandotan leaf extract,whereas broiler in group 1 (P1) and group 2 (P2) was given 3 ml and 5 ml of bandotan leaf extract, respectively. The extract was orally given once daily for 5 consecutive days. Results of analysis of variance (Anova) showed that bandotan leaf extract did not significantly (P&gt;0.05) affect carcass weight and abdominal fat of broiler. The average percentage of carcass weight in groups P0, P1, dan P2 were 73.30±3.54, 71.80±3.06, and 70.33±9.18%, respectively and the average percentage of abdominal fat in group P0, P1, dan P2 were 1.99±0.68, 2.30±0.46, amd 1.96±0.18%, respectively. Based on these results it can be concluded that bandotan leaf extract could not increase carcass weight and reduce abdominal fat of broilers.

Effect of dietary fat source and bird’s sex on performance and peroxisome proliferator-activated receptor-γ gene expression in broiler chicks

The present study was conducted to investigate the effects of different sources and levels of dietary fat and bird’s sex on performance and gene expression of peroxisome proliferator-activated receptor-gamma (PPARγ), as an adipose differentiation and development regulatory key, in broiler chicks. One-week-old broiler chicks (840: 420 males and 420 females) were randomly allocated into a factorial arrangement of treatments including 3 different fat sources (soybean oil, yellow grease, and poultry fat), 3 different fat levels (0, 20, and 40 g/kg of diet), and 2 sex categories (male and female) based on a completely randomized design with 4 replicates of 15 birds each. In addition to performance parameters, abdominal fat tissue was collected from 6 wk-old chicks and total RNA was extracted by RNX reagent. A semi-quantitative reverse transcription PCR was performed to investigate the effects of dietary treatments on PPARγ gene expression. Results showed that dietary fat source had no effect on body weight gain (BWG); however, supplementation of 20 g/kg fat into the broiler diets improved feed conversion ratio (FCR). Male chicks had higher feed intake and BWG, as well as the better FCR values than female broilers. The highest expression of PPARγ gene was detected in the abdominal fat of birds fed on diets containing soybean oil and poultry fat, and females expressed PPARγ gene higher than males. Our findings indicated that different dietary fat sources and sex might affect the development of broiler abdominal fat by interfering in PPARγ gene expression.

Effect of corn replacement with graded levels of wheat screening and enzyme supplementation on performance, blood lipids, viscosity and jejunal histomorphology of finisher broilers

An experiment was carried out to study the effect of corn replacement with five levels of wheat screening (0, 150, 300, 450 and 600 g/kg of diet) with (0.5 g/kg of diet) or without xylanase-glucanase enzyme on performance, blood lipids, viscosity and jejunal histomorphology of finisher broilers (25-42 days of age). Five hundred day-old Ross-308 male broiler chicks were fed by a standard commercial diet up to 24 days of age, then randomly assigned to 10 diets. Each diet was fed to five groups of ten chicks each. There was not significant differences in body weight gain (BWG), feed intake, and feed conversion ratio of birds fed with different levels of wheat screening (WS), whereas enzyme increased (p&lt;0.05) BWG. Different levels of WS and enzyme did not have a significant effect on relative weights of carcass, breast, thigh, and abdominal fat of broilers. Relative weights of gizzard, pancreas, small and large intestine, and relative length of jejunum and jejunal and ileal viscosity were increased (p&lt;0.05) by WS, while were decreased (p&lt;0.05) by enzyme. The serum cholesterol level decreased (p&lt;0.05) by increasing levels of WS. Jejunal histomorphological observations showed (p&lt;0.05) shorter and thicker villus and lower crypt depth by increasing levels of WS, while addition of enzyme to the diets, affected (p&lt;0.05) reversely to these parameters. The results showed that the addition of wheat screening up to an inclusion level of 600 g/kg of diet had no adverse effect on broiler performance in the finisher (25-42 d) phases whereas decreased serum cholesterol levels, increased viscosity and villus atrophy. The dietary administration of exogenous enzyme improved performance parameters and decreased viscosity and villus atrophy of broiler jejunum.

Investigation on the effect of different levels of dried sweet orange (Citrus sinensis) pulp on performance, carcass characteristics and physiological and biochemical parameters in broiler chicken

Utilization of agricultural by-products in animal nutrition is a matter of great concern. Dried sweet orange (Citrus sinensis) pulp (DCSP) is a potential source of valuable nutrients and natural antioxidants for poultry feed. In the experiment, a feeding trial was conducted in order to investigate the effect of different levels of dried orange residues in diet on broiler growth performance, carcass characteristics, blood metabolites, humoral immunity, and cecum microbial population. A total of 200 one day experimental broiler chicks were distributed into a completely randomized design (CRD) which included 5 dietary treatments with 4 replicates per each treatment and 10 birds fed in each replicate. The experimental treatments consist of a control group (without additive), 0.5%, 1.0%, 1.5%, and 2% of DCSP (residue) in diet. Weight gain, feed intake and feed conversion ratio (FCR) were measured. Blood parameters and carcass traits were measured in the postnatal 35th day. The highest level of dried orange residues in treatment 5 (T5) had significantly increased the feed intake and body weight of broilers in groups and overall during the rearing period (P>0.05). Different levels of dried orange residues had no significant effect on chicken FCR. Using of dried orange residues significantly decreased the liver and abdominal fat of broilers (P<0.05). T5 has also significantly lower level of triglyceride than the control (T1) and treatment 2 (T2) (P<0.05). In conclusion, the use of dried orange residues improved some performance (e.g. feed intake and body weight gain), decreased liver and abdominal fat and also serum triglyceride level in broiler chicken.

Meat quality and color of abdominal fat of broilers fed diets containing cashew nut meal treated with antioxidant

This experiment aimed to assess the influence of diets containing cashew nut meal stored for 35 days and treated at different storage times with 500 ppm butylated hydroxytoluene on the characteristics of breast meat and abdominal fat. The experiment followed a completely randomized design. Treatments consisted of diets containing: untreated cashew nut meal; cashew nut meal treated with antioxidant on zero day of storage, and cashew nut meal treated with antioxidant on 21 st day of storage. At 42 days old, broilers were slaughtered. Breast and abdominal fat of each bird were identified, weighed, frozen stored for subsequent analysis. The variables studied were: pH, water holding capacity, cooking losses and shear force, in the meat and color of the meat and of the abdominal fat. Treatments did not affect (p > 0.05) the evaluated parameters. However, the yellowness (component b*) of the abdominal fat was higher in birds fed the diet containing meal treated with antioxidant at storage day zero. In conclusion, the cashew nut meal can be stored for 35 days without antioxidant, but in order to achieve intense yellowness in abdominal fat of broilers 500 ppm antioxidant addition is required, at the beginning of storage.

Kualitas Karkas (Berat Karkas, Persentase Karkas Dan Lemak Abdomen) Ayam Broiler yang Diberi Kombinasi CPO (Crude Palm Oil) dan Vitamin C (Ascorbic Acid) dalam Ransum sebagai Anti Stress

The research was conducted to determine the effect of CPO (Crude Palm Oil) and Vitamin C (ascorbic acid) combination in the diet as an anti stress on broilers carcass and abdominal fat of broilers. The research was carried out in the poultry housing at UPT of Animal Science Faculty, Andalas University Padang for 42 days and 100 unsex broiler were used. The method of this research was an experiment with completely randomized design with 5 treatments and 4 replications. Replicates each consisting of 5 broilers were placed in a cage with a group size of 75 x 60 x 60cm. Results of analysis of variance showed that the combination treatment CPO and Vitamin C significantly (P&lt;0.05) on carcass weight, but the percentage of carcass, and percentage of abdominal fat treatment have different effects and not significant (P&gt;0.05). In this research the best trends CPO 3% and Vitamin C 500 ppm in the ration.

Characterization of chicken &lt;I&gt;PPARγ&lt;/I&gt; expression and its impact on adipocyte proliferation and differentiation

To characterize the chicken PPARγ gene expression and its impact on chicken adipocyte proliferation and differentiation, western blotting approach was conducted to investigate the expression of PPARγ in various chicken tissues and the difference of expression level in abdominal adipose tissues between the NEAU broiler lines divergently selected for abdominal fat content. The expression of PPARγ gene was suppressed in chicken adipocytes using RNAi technology, and the roles of PPARγ gene in the adipocytes proliferation and differentiation were investigated by MTT assay and Oil Red O staining extraction assay, respectively. After PPARγ gene was downregulated, the expression level of other transcript factors and marker genes related to the adipocyte differentiation was detected by Real-time PCR and Western blotting analyses. The results showed that PPARγ highly expressed in abdominal adipose tissue, gizzard, spleen, kidney, lowly expressed in heart, and not expressed in liver, breast muscle, leg muscle, and duodenum. Meanwhile, PPARγ expressed much higher in fat birds than in lean ones in abdominal adipose tissue at 5 and 7 weeks of age (P<0.05). RNAi analysis showed that knockdown of PPARγ gene increased chicken adipocyte proliferation and decreased cell differentiation and significantly decreased the expression levels of C/EBPα, SREBP1, A-FABP, Perilipin1, LPL, and IGFBP-2 (P<0.05). In summary, PPARγ gene may be related to the broiler abdominal fat deposition, and be probably a key regulator of chicken adipocyte proliferation and differentiation.

Blood Biochemical Indices and Productivity of Broilers on Diet Supplemented with Mannan Oligosacharide, Baker Yeast, or Combined Baker Yeast and Noni Leaves Extracts

A research was carried out to study the inclusion of MOS, inactivated baker yeast or combined baker yeast and Noni leaves extracts into corn-mungbean basal diet on broilers blood biochemical indices and productivity. Lohman MB-202 day old chicks were randomly assigned into four treatment diets i.e. 1) commercial/control diet (Dc), 2) basal diet plus MOS (DM), (3) basal diet plus inactivated baker yeast (DY), (4) basal diet plus inactivated baker yeast and Noni leaves extracts (DY+L). Treatment diets and water were given ad libitum. Whole blood were sampled on day 21 for determination of hemoglobin and haematocrit, Serum Glutamic Pyruvic Transaminases, Glutamic Oxaloacetic Transaminases, creatinine, lipid profile, alkaline phosphatase and lactic acid. Relative organs weight, abdominal fat, productivity were also determined. Feed intake, body weight and feed conversion of broilers fed DM, DY, DY+L were the same but they were lower than control diet (p<0.05). Serum triglyceride, GPT, creatinine, cholesterol, VLDL+LDLchol and HDLchol were significantly affected by the diets (p<0.05). No effect was found for other serum biochemical indices. For relative internal organs weight, a significant effect was found for heart, liver, ileum, duodenum and pancreas. These results were discussed in terms of the possible underlying mechanism. Our results here provide evidence that MOS, inactivated baker yeast alone or its combination with Noni leave extract could produce low serum TG, total cholesterol, VLDL+LDLchol, HDLchol and abdominal fat in broilers fed corn-mungbean basal diet with no negative effect on other serum biochemical indices.

Effects of microwave rendering on the yield and characteristics of chicken fat from broiler abdominal fat tissue

Microwave rendering process and effects of rendering conditions on yields and characteristics of chicken fat from broiler abdominal fat tissue were studied. Microwave rendering process could be divided into three phases: warming-up, constant temperature and heating-up phases. Increasing microwave power increased the rate of temperature rise and final temperature of chicken fat, shortened the duration of warming-up and constant temperature phase, and decreased the moisture content of chicken fat. Longer irradiation time resulted in higher final temperature, lower moisture content and darker, browner color of chicken fat. The chicken fat rendered at power level of 2.75W/g for 10min had the highest yield (70.55%) with the lowest peroxide value, acid value and thiobarbituric acid value (p < 0.05). The major fatty acids in chicken fat obtained at optimum conditions were oleic acid (45.73%), palmitic acid (26.13%), linoleic acid (15.12%), palmitoleic acid (6.07%), and stearic acid (5.81%).

Color and fatty acid profile of abdominal fat pads from broiler chickens fed lobster meal

Consumer demands for food products enriched with healthful n-3 fatty acids are steadily increasing. Feeding marine byproducts may provide an economical means of increasing the long-chain n-3 content of broiler tissues. A study was conducted to evaluate the effect of dietary lobster meal (LM) on the color and fatty acid profile of broiler chicken fatty tissue. Broilers were fed increasing levels (0, 2, 4, 6, 8, and 10%) of LM for 35 d. Fat pad samples were collected at slaughter and color and fatty acid concentrations were determined. A linear effect was found of LM on red coloration (P < 0.05) as dietary LM increased. Fat pad eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels also increased (P < 0.0001) in a linear fashion. The essential long-chain fatty acids were lower for the 10% LM diet (0.37 mg of EPA/g; 0.16 mg of DHA/g) compared with the 8% LM diet (0.51 mg of EPA/g; 0.27 mg of DHA/g). Using lobster meal as a feed ingredient resulted in broiler abdominal fat pads with a favorable increase in n-3 fatty acids.

Effects of dietary lipids and Clostridium butyricum on serum lipids and lipid-related gene expression in broiler chickens

The effect of dietary lipids and Clostridium butyricum supplementation on circulating lipids and the transcription of selected genes involved in lipid metabolism were investigated in broiler chickens. One hundred and sixty-day-old broilers (Arbor Acres) were divided into four treatment groups in a 2 × 2 factorial arrangement and fed four diets with two lipid sources (soybean oil or fish oil) and two levels of C. butyricum (0 or 5 g/kg) for a period of 6 weeks. Serum concentrations of total cholesterol and low-density lipoprotein cholesterol were lower (P < 0.05) in broilers fed diets containing fish oil than in those fed diets containing soybean oil. Fish oil significantly reduced (P < 0.05) hepatic fatty acid synthase and lipoprotein lipase (LPL) activities in abdominal fat. In contrast, fish oil significantly increased (P < 0.05) breast muscle LPL activity and hepatic peroxisome proliferator-activated receptor-α and LPL gene expression. The addition of C. butyricum significantly increased (P < 0.05) LPL activity in abdominal fat and liver-type fatty acid-binding protein gene expression in jejunal mucosa. The results of this study indicated that the reduced abdominal fat in broilers fed fish oil as observed may be due to augmented hepatic fatty acid catabolism and lower hepatic fat synthesis. The increased intramuscular fat content in breast muscle of broilers fed C. butyricum as described may be the result of enhanced fatty acid uptake.

Influence of Dietary Cinnamon Oil Supplementation on Fatty Acid Composition of Liver and Abdominal Fat in Broiler Chicken

Dalkilic, B., Ciftci, M., Guler, T., Cerci, I.H., Ertas, O.N. and Guvenc, M. 2009. Influence of dietary cinnamon oil supplementation on fatty acid composition of liver and abdominal fat in broiler chicken. J. Appl. Anim. Res., 35: 173–176. The potential effects of essential oil from cinnamon on fatty acid compositions of liver and abdominal fat in broilers were studied. Two hundred and forty 5-d-old commercial broiler chicks (Ross–308) were divided into 4 equal groups of 60 birds in each and randomly assigned to four treatment diets with four replicates. Experimental groups were; corn-soybean meal basal diet (Control), basal diet supplemented with 10 mg/kg Avilamycin (Antibiotic), 500 or 1000 ppm of cinnamon oil (C500, C1000). Poly unsaturated fatty acid (PUFA), omega-3 and omega-6 fatty acid levels of liver lipids were found higher but saturated fatty acid (SFA) levels were found lower in cinnamon oil added groups. The lowest mono unsaturated fatty acid (MUFA) level and the highest SFA level of abdominal fat were found in control group. Supplementation of cinnamon oil to diets could be considered as a natural alternative for producing poultry meat with more desirable PUFA.

Early energy and protein reduction: effects on growth, blood profiles and expression of genes related to protein and fat metabolism in broilers

1. A total of 320-d-old Ross broilers were used in a 6-week study to investigate the effects of feeding lower energy and protein diets from d 8 to 14 on growth performance, blood profiles, and gene expression of leptin and myostatin. 2. Broilers were randomly allotted to 4 treatments, each treatment applied to 4 pens with 20 birds in each. During first week, all the birds were fed on a common starter diet (13·4 MJ ME/kg, 230 g/kg CP and 11·0 g/kg lysine). The birds were then subjected to their respective treatment diets from d 8 to 14. Treatment diets comprised two ME levels, 13·4 and 12·0 MJ/kg, each with two levels of CP, 230 and 184 g/kg. This was followed by feeding common starter and finisher diets for the last 4 weeks. 3. Dietary protein reduction resulted in poor performance and feed efficiency while energy reduction resulted in poor feed efficiency between d 8 and 14. From d 14 to 42 birds previously fed diets lower in energy and protein showed similar body weight gain and feed intake to well-fed birds. Moreover from d 8 to 14, birds fed on energy and protein-reduced diets had lower nutrient metabolisability coefficients. 4. The blood urea nitrogen (BUN) and relative weights of heart and breast muscle were lower in birds fed protein-reduced diets while energy reduction resulted in lower plasma glucose, abdominal fat and intestinal weight at d 14. At d 42, birds fed on the protein-reduced diets had lower BUN, breast muscle weight and small intestine length, while feeding on the energy-reduced diets resulted in lower abdominal fat. 5. Upregulated myostatin mRNA expression in breast muscle and downregulation of leptin mRNA expression in abdominal fat were observed in birds fed on protein and energy-reduced diets, respectively. 6. In conclusion, early nutrient reduction affected growth performance and produced lesser abdominal fat in broilers. Moreover, early energy and/or protein reduction could change muscle and fat metabolism by regulating the expressions of myostatin and leptin.