Effect of hexoestrol implantation and body size on the chemical composition and body components of chickens

Two groups of meat‐type cockerels, 56 d of age, from the same hatch but of different mean live‐weights (1135 g ± SD 96.2 and 544 g ± 72.0) due to differences in earlier nutritional treatments were implanted with hexoestrol to determine the effects on food consumption, live‐weight gain, carcass gain, chemical composition of carcass and offal, and weight of some body components. Replicate groups were slaughtered prior to implantation and at the end of the 28‐d experimental period.

Implantation with a single 15 mg hexoestrol pellet resulted in the following significant differences compared with untreated controls: increases in food consumption, live‐weight gain, carcass weight and weight of offal of 21.5, 14.2, 8.2 and 16.6 per cent respectively; poorer food conversion, higher total fat in the carcass, offal and total body and, relative to body weight, heavier livers and lighter hearts, gizzards, legs and necks. The increased fat in treated chickens accounted for all the increased body weight and carcass weight.

In comparisons of small and large chickens there was no significant difference in live‐weight gain during the 28‐d experimental period. At both 56 and 84 d of age the dressing percentages were lower and the weights relative to body weight of offal, liver, shanks and gizzards were higher in small than in large chickens. Percentage moisture was significantly higher in the total bodies and carcasses of small chickens, while percentage fat was significantly lower in the carcasses of small chickens at both 56 and 84 d and in the total bodies and offals at 56 d.     

Rice bran lysolecithin as a source of energy in broiler chicken diet

1. Rice bran lysolecithin (RBL) was evaluated in broiler chicken diets. In the first experiment, RBL was included in diet at 0, 0·5, 2, 8 and 32?g/kg and fed to 250 broiler chickens from 0 to 42?d of age. In the second experiment, RBL was fed at 0, 25 and 50?g/kg diet to 405?day-old broiler chickens until 21?d of age, while during the finisher phase (22–35?d of age) chickens receiving each concentration of RBL were given all three concentrations of RBL in a 3?×?3 factorial manner. The diets were isocaloric.

2. Body weight, food consumption and food conversion efficiency were unaffected by feeding RBL, while the weight of pancreas increased at ≥2?g/kg of RBL in diet (experiment 1). In experiment 2, body weight was greater in the chickens receiving RBL at either 25 or 50?g/kg (21?d) and 50?g/kg (35?d of age). At 21?d of age, food consumption was greater at 25 or 50?g RBL/kg diet, while food conversion efficiency improved with 50?g RBL/kg diet.

3. Fat digestibility increased with RBL at 32?g/kg (experiment 1) and ≤25?g/kg (experiment 2). Rice bran lysolecithin increased ready to cook weight at 50?g/kg during starter phase and decreased abdominal fat at 25 and 50?g/kg during finisher phase (experiment 2). Liver and meat fat content were not affected.

4. It is concluded that lysolecithin from rice bran oil could be used as energy supplement in broiler chicken diet.     

Comparison of plasma very low density lipoproteins and lipogenic enzymes as predictors of fat content and food conversion efficiency in selected lines of broiler chickens

1. Activities of lipogenic enzymes and plasma very low density lipoprotein (VLDL) concentrations were measured in lines of chickens with large differences in food conversion efficiency (FCE) and body fat.

2. Hepatic activities of malate dehydrogenase [EC 1.1.1.40 (MD)] and ATP citrate lyase [EC 4.1.3.8 (CL)] were correlated with the proportion of both abdominal and total body fat (r = 0·50) but were poorly correlated with gain:food ratio.

3. Activities of MD and CL in plasma were low and variable and were not correlated with any other characteristics.

4. Plasma VLDL concentration was significantly correlated with the proportion of abdominal and total body fat (r = 0·59), and gain: food ratio (r = 0·36).

     

Growth performance,carcass criteria,and serum biochemical parameters of broiler chickens supplemented with either synbiotic or prebiotic under hot climatic conditions

ABSTRACT

1. Two separate experiments were conducted to evaluate the efficacy of either prebiotic or synbiotic on growth performance, carcass yield, organ weights, and serum metabolic profile of broilers under hot climatic conditions.

2. In experiment 1, 150 1-d-old Ross 308 male broiler chickens were fed dietary synbiotic (Biomin® IMBO, 0, 1 or 1.5 g kg^?1 of the starter diets and 0, 0.5 or 0.75 g kg^?1 of the grower diets) for 6 weeks. In experiment 2, 150 1-d-old Ross 308 male broiler chickens were fed dietary prebiotic (Mannan oligosaccharide 0, 0.5 or 1 g kg^?1 of the starter diets and 0, 0.25 or 0.5 g kg^?1 of the grower diets) for 6 weeks. Each treatment had 10 replicates containing 5 broiler chickens each.

3. Supplementation of synbiotic at 1 or 1.5 g kg^?1 feed to broiler diets during 1–21 d and 0.5 or 0.75 g kg^?1 feed, respectively, during 22–42 d improved (P < 0.01) body weight gain, feed conversion ratio (FCR), and decreased (P < 0.01) abdominal fat, serum total cholesterol, and low-density lipoprotein (LDL) cholesterol levels in experiment 1.

4. Similarly, supplementation of the prebiotic at 0.5 or 1 g kg^?1 in broiler diets during 1–21 d and 0.25 or 0.50 g kg^?1 feed, respectively, during 22–42 d improved (P < 0.01) body weight gain, FCR, and decreased (P < 0.01) abdominal fat, serum cholesterol, and LDL-cholesterol levels in experiment 2.     

Development of divergent lines of lean and fat broilers using plasma very low density lipoprotein concentration as selection criterion: The first three generations

1. Male and female broilers of a pure line were selected over three generations on the basis of high or low plasma very low density lipoprotein (VLDL) concentration at 7 weeks of age.

2. Heritability of plasma VLDL was high (h ² = 0·50 ± 0·08) and by the third generation mean values in the two lines differed by a factor of 2·5.

3. Correlated responses to selection for low plasma VLDL included a relative decrease in abdominal fat and total body lipid and an increase in body protein, together with improvements in the conversion efficiences of food and dietary protein.

4. There was no difference between the lines in 7‐week body weight.

     

Effects of ambient temperature on growth performance and carcass traits of male growing White Pekin ducks

ABSTRACT

1. An experiment was conducted to investigate the effects of ambient temperature on growth performance and carcass traits in male growing Pekin ducks from 14 to 42 d of age in order to establish their optimal temperature requirements.

2. A total of 216 14 d old male White Pekin ducks were allocated randomly to six environmentally controlled chambers with ambient temperature set at 20°C, 22°C, 24°C, 26°C, 28°C, and 30°C from 14 to 42 d of age, respectively.

3. As ambient temperature increased from 20°C to 30°C, the body weight and weight gain decreased linearly or quadratically (P < 0.05) and was accompanied by linearly decreasing feed intake (P < 0.05). According to broken-line regression, the upper critical level of ambient temperature during the growing period for body weight, weight gain, and feed conversion ratio were 27.4°C, 27.4°C, and 26.0°C, respectively.

4. The weight of breast meat, leg meat, and abdominal fat decreased linearly or quadratically as ambient temperature increased and declined to a minimum when the temperature increased to 30°C (P < 0.05). The percentage of breast meat and abdominal fat showed a linear or quadratic decreasing response to increasing temperature, but leg meat percentage increased as temperature increased and reached maximum at 30°C (P < 0.05). According to broken-line regression, the upper critical ambient temperatures during the growing period for breast meat weight and percentage were 25.5°C and 25.6°C, respectively.

5. It was concluded that both growth performance and breast meat of growing ducks were sensitive to increasing ambient temperature and this should be kept below the upper critical temperature during the growing period in order to optimise growth performance and carcass traits at market age.     

The effects of temperature on broilers: A simulation model of the responses to temperature

1. The effects of post‐brooding temperature (15 to 27 °C), age (42 to 56 d) and dietary nutrient and concentration energy (11.7 to 13.3 MJ/kg for the finisher diet) on the cumulative food intake and body weight responses of broilers were combined in a predictive simulation model, using multiple regression techniques.

2. An economic model of these responses was developed in which the temperature and age at slaughter are optimised, given food and live body weight prices.

3. If a finisher diet of 13.3 MJ ME and 199 g protein/kg costing 150 £/tonne is fed, and provided the grower diet contains 13.5 MJ and 221 g protein/kg, the optimum temperature is 21 to 22 °C for male and female broilers slaughtered at 61 and 54 d respectively with a live body weight value of £0.50/kg.     

Performance,breast meat yield and abdominal fat deposition of male broiler chickens fed diets supplemented with DL‐xnethionine or DL‐xnethionine hydroxy analogue free acid

1. An experiment was conducted to compare the relative bioefficacy of DL‐methionine hydroxy analogue free acid (DL‐MHA‐FA) with DL‐methionine in broiler chickens. Responses used for comparison were weight gain and food efficiency between 7 and 35 d of age, and breast meat deposition, food cost per kg of breast meat, and abdominal fat at 41 d of age.

2. A total of 2160 seven‐day‐old male broiler chicks were used. The feeding programme consisted of a starter diet from 7 to 21 d, and a finisher diet till the end of the experiment. The starter basal diet contained 6.1 g/kg total sulphur‐containing amino acids (TSAA), and an estimated metabolisable energy (ME) content of 13.2 MJ/kg. The finisher diet contained 5.8 g/kg TSAA and an estimated ME content of 13.6 MJ/kg. Four concentrations of DL‐methionine and DL‐MHA‐FA were added at 0.5g/kg increments on an equimolar basis. Therefore, there were 9 experimental treatments which were each applied to 6 replicates of 40 chicks. Weight gain and food efficiency were determined at 35 d of age. Breast yield and carcase fat were measured at 41 d.

3. Significant responses to graded amounts of both methionine sources were observed in weight gain, food efficiency, breast meat percentage, and food cost per kg of breast meat. The responses fitted exponential regression curves. Based on the regression coefficients, equimolar bioefficacy of DL‐MHA‐FA relative to DL‐methionine was 80% for daily gain, 83% for food efficiency, 51% for breast meat yield, and 66% for food cost per kg of breast meat. Differences between the 2 sources were significant (P< 0.05) for breast meat yield and food cost per kg of meat and (P< 0.10) for food efficiency.     

Energy and nitrogen metabolism of broilers selected over ten generations for increased growth rate,food consumption and conversion of food to gain

1. Energy and nitrogen (N) metabolism were studied in 6‐week‐old male birds taken from 4 lines of chickens selected for 10 generations for increased weight gain (line W), increased food consumption (line F), increased conversion of food to gain (line E) or at random (controls, line C).

2. Calorimetric measurements were made 8 times on each line while fed ad libitum in large open‐circuit respiration chambers for 3 d, and 11 to 13 times without food in smaller closed‐circuit respiration chambers for 24 h.

3. The F line ate 60% more food, produced 90% more excreta and 34% more heat and retained 80% more energy and 35% more N in their bodies than lines E and C. Line W was intermediate.

4. When differences in body weight were taken into account, the E and W lines had lower heat production than the C line, while the F line ate 40% more food, produced 30% more heat and retained 70% more energy and 30% more N than the E line.

5. In lines W, F, E and C respectively, the mean metabolisability of dietary energy (%) was 69·4, 62·9, 70·1 and 67·8 ; the fasting heat production (mean ± SE) was 481 ±9, 569 ± 10, 485 ± 9, and 508 ± 9 kJ/kgW d; the net availability of metabolisable energy (NAME) was 0·68 ± 0·05, 0·76 ± 0·04, 0·85 ± 0·06 and 0·73 ± 0·04; the estimated daily maintenance energy requirements were 671 + 15, 866 ± 14, 701 ± 13, and 742 ± 11 kJ ME/ kgW; and the proportion of N retained per unit increase in N intake was 0·38 ± 0·08, 0·50 ± 0·06, 0·56 ± 0·10 and 0·53 ± 0·06. 6. The contribution of line differences in the above traits to large line differences in efficiency of food utilisation is discussed.

     

Effect of calorie to protein ratio on the degree of fatness in broilers fed on practical diets 1

Three trials were carried out with broilers to compare the effect of different calorie to protein (C : P) ratios in practical‐type diets with the amount of carcass fat at 8 or 9 weeks of age. The latter was estimated on the basis of the concentration of fat or dry matter in a sample of back skin and by visually scoring the amount of abdominal fat.

Rearing broilers on diets containing protein levels slightly above or below the accepted optimum did not affect growth rate. However, in most comparisons the high‐protein diets brought about better food to gain ratios, and in all comparisons they produced relatively lean carcasses. Increasing or decreasing the protein level of finisher diets resulted in a decrease or increase, respectively, in the degree of fatness. A 2‐week period was sufficient to create or reverse these trends in a pronounced manner.

Dietary oil supplementation per se did not increase the amount of carcass fat as long as the C : P ratio was kept constant. If there existed any consistent trend at all, it appeared to act in the opposite direction, towards a decrease in carcass fat.     

Genetic evaluation of meat quality traits and their correlation with growth and carcase composition in Japanese quail

1. Estimates of heritability, genetic and phenotypic correlations of performance and meat quality traits were obtained in a population of Japanese quail using restricted maximum likelihood (REML) procedures.

2. The heritability estimates for body weight (BW) traits ranged from 0·15 at hatch to 0·42 at six weeks. For carcase composition traits, heritability estimates ranged from 0·12 for carcase yield to 0·26 for abdominal fat yield and for meat quality traits they ranged from 0·18 for drip loss to 0·54 for yellowness of the meat.

3. Negative genetic correlations were found between BW and carcase traits with ultimate pH and drip loss ranging from ?0·01 (BW at hatch) to ?0·40 (skin yield). Redness and yellowness showed negative genetic correlations with BW and carcase traits, whereas the genetic correlations with lightness were positive (from 0·04 to 0·43).

4. Shear force and cooking loss showed positive genetic correlations with carcase, breast, abdominal and skin yield.

5. In conclusion, meat quality traits have the potential to be improved through genetic selection but selection for higher BW and carcase composition may reduce the meat quality of Japanese quail through reducing redness, ultimate pH and intramuscular fat and increasing lightness, shear force and cooking loss of the meat.     

Effects of diet acidification and xylanase supplementation on performance, nutrient digestibility, duodenal histology and gut microflora of broilers fed wheat based diet

1. The objective of this experiment was to study the influences of xylanase and citric acid on the performance, nutrient digestibility, digesta viscosity, duodenal histology, and gut microflora of broilers fed on a wheat based diet.

2. The experiment was carried out as a 2?×?3 factorial arrangement with two concentrations of xylanase (0 and 200?mg/kg) and three concentrations of citric acid (0, 20 and 40?g/kg). A total of 408 one-day-old chickens with similar body weight were distributed into 24 pens with 17 birds/pen. Each dietary treatment was given to 4 replicate pens from 0 to 24?d of age. To determine the apparent nutrient digestibility, chromic oxide (3?g/kg) was added to the diets as an indigestible marker.

3. Xylanase significantly increased body weight gain at 24?d of age by 1·4% and improved gain-to-feed (G:F) by 3·6%. The inclusion of 40?g/kg citric acid decreased feed intake and body weight gain by 15·4% and 11·8%, respectively. The inclusion of 20?g/kg of citric acid decreased feed intake, but it did not affect body weight gain of broilers at 24?d of age. The inclusion of 20 and 40?g/kg citric acid improved G:F by 3·8 and 4·3% respectively. Xylanase significantly decreased the viscosity of digesta and improved retention of DM, CP, and energy.

4. Xylanase and citric acid did not have any effect on the histo-morphology of the duodenum and intestinal microbial population.

5. In conclusion, citric acid at 20?g/kg decreased feed intake, did not have a negative effect on body weight gain, and improved G:F. Xylanase decreased digesta viscosity, increased nutrient retention and consequently improved performance of broilers fed on a wheat based diet.     

Effects of cultivar,pelleting and enzyme addition on nutritive value of barley in poultry diets

1. The effect of pelleting process and Trichoderma viride enzymes (TVE) addition on apparent metabolisable energy, corrected for nitrogen balance (AMEn) and on productive value of practical diets containing 40 and 45% of three different barley cultivars and one wheat were studied in poultry.

2. The effect of the pelleting process on AMEn was inconsistent and was dependent on the cereal included and the addition of enzyme.

3. The growth trial showed a significant effect of enzyme addition to pelleted diets over the whole growth period (0 to 42 d). Addition of TVE improved weight gain and food efficiency by 1.3% and 2.9%, respectively and decreased food intake by 1.6% between 0 and 22 d. In the finisher period (23 to 42 d) TVE improved efficiency by 2.8% and reduced food intake by 2.9%.

4. The incidence of sticky droppings was related to the viscosity of barley used, and enzyme supplementation reduced it. Both pelleting and enzyme addition increased dry matter content of excreta.

5. At the end of the experiment, 14 animals per treatment were slaughtered and carcass yield, viscera weight and abdominal fat were determined.     

Food intake and growth in chickens given food in the wet form with and without access to drinking water

1. Individually caged growing chickens were offered a commercial grower food mixed with 1–5 to 2^‐25 times the weight of water and the effects, compared to giving the same food in air‐dry form, on food intake, body weight gain and carcase composition were investigated.

2. Male broilers (24) were given either a grower food in the air‐dry form with access to drinking water or the same food mixed with 2–0 parts of water (700 g water/kg of mixed food) with no drinking water from 28 to 49 d of age. From 49 to 63 d all birds were given dry food and drinking water and were then killed for carcase analysis. Food intake and weight gain were significantly increased during the wet‐feeding period, as was carcase protein but not abdominal or carcase fat at the end of the experiment.

3. Five male broilers were given each of 5 dietary treatments containing 0 (control), 1.5, 1.75, 2.0 and 2.25 times added water (640, 673, 700 and 723 g water/kg) from 28 to 49 d. Food intakes, body weight gains and carcase weights were significantly increased for all water additions compared with dry food, but there were no significant differences between different water additions.

4. Female broiler chicks responded to wet feeding (700 g water/kg) in a similar manner to males and the dry matter approximate digestibility was increased from 0.65 for the dry food to 0.73 for the wet.

5. Cockerels of an egg‐laying strain did not increase their intake of dietary dry matter when it was fed in the wet form (700 g water/kg), but there was a significant increase in body weight gain.

6. Male broilers were offered wet food (700 g water/kg) with or without access to drinking water. There was equal stimulation of food intake, growth and carcase weight with both wet‐feeding treatments.

7. Providing food mixed with sufficient water to give a porridge‐like consistency significantly increased weight gains in each of the five experiments and significantly improved food conversion efficiency in three of the five. It is not necessary to withold drinking water in order to obtain this effect.     

Sunflower seed meal as a substitute for soybean meal in commercial broiler chicken diets

1. An experiment was conducted to study the possibility of replacing soybean meal (SBM) with sunflower seed meal (SFM) in broiler chick diets. The SBM in broiler starter (317.9 g/kg) and finisher (275.4 g/kg) diets was replaced with SFM at 33, 67 and 100% on an iso-caloric and iso-nitrogenous basis using sunflower oil to balance the energy content of the diets. The metabolisable energy levels used in the diet were considerably less than the recommended levels for broilers. Each experimental diet was fed ad libitum from 2 to 42 d of age to 8 replicates of 5 birds. Parameters studied included amino acid and apparent metabolisable energy contents in food ingredients, body weight, food intake, food efficiency, leg abnormality score, dry matter digestibility, carcase traits, relative weight and length of intestine, fat and protein content in liver and serum biochemical profile. 2. SFM had higher concentrations of calcium, phosphorus, methionine and cystine and lower energy content than SBM. 3. Replacement of SBM with SFM up to 67% in starter and 100% in finisher diets did not affect weight gain. Total and 67% replacement of SBM with SFM depressed food efficiency at 21 and 42 d of age, respectively. Food intake was significantly higher in SFM-based diets than in the SBM reference diet at 21 and 42 d of age, except in groups given SFM100 at 21 d of age. In the latter group, the food intake was similar to that on the SBM reference diet. The digestibility of dry matter decreased with increased levels of SFM in the diet. 4. The relative weights of giblet, liver and abdominal fat, length of intestine, activity of alkaline phosphatase, concentrations of calcium and inorganic phosphorus in serum were not influenced by incorporation of SFM in the broiler diet. 5. The ready to cook yield and liver fat content decreased, while the relative weights of gizzard and intestine and protein content in liver increased, with increasing levels of SFM in the diet. 6. The concentration of HDL cholesterol increased while the concentration of LDL cholesterol decreased with increasing content of SFM (> or =67% of SBM) in diet. The serum protein concentration decreased progressively with increase in dietary SFM. The concentrations of protein and triglycerides in serum were lowest in groups receiving SFM100. 7. Body weight gain was not affected by total replacement of SBM with SFM at 42 d of age. However, considering food efficiency, carcase yields, serum lipid profile and level of supplemental fat in diet, it is concluded that SFM can replace up to two-thirds of soybean, corresponding to inclusion of 345 and 296 g SFM per kg for starter and finisher phases, respectively.     

Body weight and/or fatness as potential determinants of the onset of egg production in broiler breeder hens

1. In four trials during consecutive years individually‐caged birds were weighed at first egg, and in the first two trials they were then killed to determine abdominal and skin fat, in order to establish whether there is a minimal body weight and/or body fat pool required for the start of egg production in broiler breeder hens.

2. There were negative correlations ranging from significant to negligible between body weight and age at first egg. For birds of the same strain on a conventional food restriction regimen, the average weight range at first egg in the four trials was 3·3 to 3·7 kg, which may be a strain characteristic.

3. In spite of severe food restriction, all birds were very fat at first egg. The correlations between fat concentration and age at first egg were negative.

4. In mature pullets a minimum concentration of stored, easily mobilised fat may be essential for yolk formation and ovulation.

     

Lysine restriction during grower phase on growth performance,blood metabolites,carcass traits and pork quality in grower finisher pigs

Abstract

The effects of lysine restriction during grower phase and realimentation during finisher phase on growth performance, nutrient digestibility, blood metabolites, carcass traits and pork quality were studied. Sixty-four pigs (two castrated males and two females per pen) weighing 34.34±5.22 kg were assigned to four dietary treatments. During grower (35–55 kg), pigs were fed isoenergetic lysine-restricted diets. The different lysine content of diets were 0.950 (NRC recommendation), 0.760, 0.665 and 0.570%, corresponding to lysine restriction of 20, 30 and 40%. Then all pigs were fed with common finisher 1 (55–85 kg) and 2 (85–115 kg) diets. Lysine restriction during the grower phase resulted in poor performance and lower concentration of blood metabolites but improved the nutrient digestibility and efficiency of lysine utilization. Compensatory growth response in terms of improved weight gain and feed efficiency was observed in pigs previously fed lysine-restricted diets during finisher 1, but the concentration of blood urea nitrogen and total protein were lower. No differences in growth performance, digestibility of nutrients and blood metabolites were noted during finisher 2. Lysine restriction of grower diets decreased the dressing percentage (quadratic, P=0.024), and protein content of longissimus muscle (linear P=0.034, and quadratic P=0.009). Thus, it could be concluded that pigs subjected to lysine restriction during grower phase exhibited compensatory growth responses in weight gain and improved efficiency of feed and lysine utilization for weight gain and lean accretion during finisher phase.     

Effect of dietary levels of rapeseed meal and polyethylene glycol on the performance of male broiler chickens

1. In a 5 × 2 factorial experiment, the performance of male broiler chickens given starter (1 to 21 d) and finisher (21 to 42 d) diets containing five concentrations (0, 74.5, 149.0, 223.5 and 298.0 g/kg) of rapeseed meal (RSM) and two concentrations (0 and 15 g/kg) of polyethylene glycol (PEG) was measured.

2. Bodyweight gain and food intake decreased (P<0.01) with increasing dietary RSM both in the starter and finisher phases.

3. The relative weights of thyroid glands, liver, heart and the ratio of water to food intake increased (P<0.01) while the dressing percentage, abdominal fat‐pad weight and the feather condition score decreased (P<0.01) with increasing dietary RSM.

4. The mortality rate was increased (P<0.05) on diets containing 149 g/kg or more of RSM. The main causes of deaths and culling on the high RSM diets were enlarged livers and hearts, liver haemorrhage and leg disorders.

5. The inclusion of 15 g/kg PEG in the starter diets increased (P<0.01) bodyweight gains and food intake. It also increased (P<0.05) water consumption between 37–39 d, faecal moisture content at 40 d and the haemoglobin content in blood.

6. There were no interactions between the dietary concentrations of RSM and PEG on growth and other variables measured.     

Effects of fermented plant product on growth performance, some blood variables, carcase characteristics, and intestinal histology in broilers

1. Fermented plant product (FPP) is a natural fermented food which is produced from a mixture of fermented fruit and vegetables, and rice bran (1:9).

2. To investigate the effects of FPP on growth performance, some blood variables, carcase characteristics and intestinal histology were determined in 192 broilers. They were divided into 4 groups, with 4 replicates of 12 chicks each; the chicks were provided ad libitum access to a diet consisting of 0, 0·5, 2·0 and 4·0% dietary FPP.

3. The crude protein and metabolisable energy concentrations of these diets were adjusted to 230?g CP/kg and 13·40?MJ ME/kg for the 7 to 21?d old chicks, and 200?g CP/kg and 13·40?MJ ME/kg for the 22 to 49?d old chicks, respectively.

4. At 49?d of age, feed intake, body weight gain and feed efficiency tended to increase with increase in FPP concentrations. Feed intake increased in the 4·0% dietary FPP group, BW gain increased in the 2·0% and 4·0% dietary FPP groups and feed efficiency increased in all experimental groups.

5. There were no differences among diets in the blood variables and carcase characteristics, except for total visceral organ weight, increased in all experimental groups.

6. Most of the intestinal villus heights, villus areas, epithelial cell areas and cell mitosis tended to increase with increase in FPP concentrations; duodenal villus height and cell mitosis in the 2·0 and 4·0% dietary FPP groups, and jejunal cell mitosis in all experimental groups were significantly increased. Compared with flat cells on the villus apical surface in the 0% FPP group, all experimental groups had protuberant cells in all intestinal parts.

7. In conclusion, hypertrophy of the villi and epithelial cells was observed in the present study, indicating improved growth performance, especially in the 4·0% dietary FPP group. Furthermore, increased total visceral organ weights suggested that FPP has no harmful effects on broilers.     

Effect of protein level on performance,nitrogen utilisation and carcass composition in finisher pigs

Abstract

For 6 weeks, 256 female finisher pigs (initially 53.9 kg) were fed four dietary treatments of 136, 148, 159 and 168 g crude protein (CP)/kg diet. The latter diet was the 159 g CP/kg diet supplemented with dispensable amino acids, to study the effect of excess CP. Week 4 included use of metabolic cages. Feed intake, gain and feed utilisation were not significantly affected. Plasma urea (P < 0.001) and urinary nitrogen (P = 0.01) decreased linearly by lowering CP. The weight of the carcass tended to increase linearly by reducing CP, but neither nitrogen retention nor carcass meat percentage and back fat depth differed among treatments. In conclusion, the study indicated that CP could be decreased to 136 g/kg as-fed for growing pigs in the weight range 50–100 kg without negative impact on growth performance and carcass traits. Moreover, leanness was not affected by excess CP.