The growth and carcass characteristics of crosses between Aabio and Tegal ducks and Muscovy and Pekin drakes

1. The growth and food utilisation of Pekin, Alabio and crosses between Muscovy or Pekin drakes and Alabio or Tegal ducks were recorded up to 20 weeks of age on a high plane of nutrition. Ducks were killed at 6, 10 and 16 weeks of age for carcass analysis.

2. The weight of Alabio ducks at 12 weeks of age was increased by 40 and 48% by crossing with Muscovy and Pekin respectively. Pekin crosses grew faster to 8 or 12 weeks of age than Muscovy crosses but after 17 weeks of age there was no significant difference in weight. Food utilisation for Muscovy crosses was generally better at all ages.

3. Both at a given age and per unit of carcass weight, Muscovy crosses contained less fat and as a consequence more protein and ash, and a higher proportion of breast meat than Pekin crosses. Proportion of fat in Muscovy × Tegal ducks increased only slightly with carcass weight, while it decreased in Muscovy × Alabio ducks.     

Genetic parameters from factorial cross breeding in two duck strains (Anas platyrhynchos) brown Tsaiya and Pekin,for growth and fatty liver traits

1. A total of 655 mule ducklings were produced in three hatches by artificial insemination of common duck females Brown Tsaiya and Pekin “Alienor” and of their 2 reciprocal crossbreds with Muscovy semen.

2. They were fed ad libitum until 6 weeks, then restricted to one meal per day until day 75 and afterwards preforce fed until day 84 and subsequently force fed by 2 crammers, twice a day, from the age of 85 d and for a maximum of 13 d.

3. Body weight at hatching, 28 d, 56 d, 75 d, 84 d and at slaughter, the number of force‐fed meals, the “paletot” weight, the fatty liver weight, the fat release rate after sterilisation of a 60 g portion of liver and the serous melting rate were measured individually.

4. Significant dam genotype and hatch effects were present for all traits. The crammer effect on force feeding traits was also significant. For mule ducks from Brown Tsaiya, Tsaiya X Pekin, Pekin X Tsaiya and Pekin dams respectively, mean body weight was 2356, 3219, 3137 and 3801 g at 12 weeks, “paletot” weight was 1585, 2111, 2110 and 2470 g, fatty liver weight was 441, 585, 563 and 641 g, fat release rate was 35·1, 40·5, 38·2 and 46·0%.

5. The estimated differences between Pekin and Tsaiya genetic effects in their mule progeny were significant and in favour of the Pekin, except for the number of force fed meals and for the serous melting rate. Grandmother genetic effects were not significant, but maternal heterosis h ^m was in general significant and favourable: it was 8·5% for birth weight, about 4% for growth traits and “paletot” weight, 6·2% for fatty liver weight and – 2·8% (not significant) for fat release rate. A crossbreeding system between a heavier Pekin breed and Tsaiya would be worth considering to improve the fatty liver production of mule ducks.     

Choline requirements of male White Pekin ducks from 21 to 42 d of age

1. A dose–response experiment with 6 dietary choline concentrations (0, 342, 779, 1285, 1662 and 1962 mg/kg) was conducted with male White Pekin ducks to estimate the choline requirement from 21 to 42 d of age.

2. Ninety 21-d-old male White Pekin ducks were allotted to 6 dietary treatments, each containing 5 replicate pens with three birds per pen. At 42 d of age, final weight, weight gain, feed intake and feed/gain were measured. Liver was collected to determine total liver lipid, triglyceride and phospholipids.

3. Significant positive effects of dietary choline on final weight, weight gain and feed intake were observed. In addition, dietary choline supplementation significantly decreased liver lipid and triglyceride content and increased liver phospholipids of Pekin ducks.

4. According to broken-line regression analysis, the choline requirements of male White Pekin ducks from 21 to 42 d of age for weight gain, feed intake and total liver lipid were 980, 950 and 1130 mg/kg. Pekin ducks needed more choline to prevent excess liver lipid deposition than to maintain growth.     

Threonine requirement of White Pekin ducks from hatch to 21 d of age

1. A dose-response experiment with 5 dietary threonine concentrations (5.0, 5.8, 6.6, 7.4 and 8.2 g/kg) was conducted to estimate the threonine requirement of White Pekin ducks from hatch to 21 d of age.

2. A total of 240 one-d-old male White Pekin ducks were allotted to 5 experimental treatments and each treatment contained 6 replicate pens with 8 ducks per pen. Ducks were reared in raised wire-floor pens from hatch to 21 d of age. At 21 d of age, growth performance and intestinal morphology were determined.

3. The weight gain and feed intake of Pekin ducks increased and feed/gain of these birds decreased linearly or quadratically as dietary threonine increased from 5.0 to 8.2 g threonine/kg. Compared to ducks fed on diets containing 5.0 g threonine/kg, ducks given diets containing 7.4 g threonine/kg had higher villus height in duodenum, jejunum and ileum.

4. The threonine requirements for weight gain of White Pekin ducks from hatch to 21 d of age was estimated to be 6.72 g/kg when dietary crude protein concentration was 189.8 g/kg and threonine supply was critical for maintaining intestinal structure of these birds.     

Threonine supplementation reduces dietary protein and improves lipid metabolism in Pekin ducks

1. This study was conducted to investigate the efficiency of threonine (Thr) supplementation on reducing dietary crude protein (CP) content and the effects of Thr on lipid metabolism in Pekin ducks. The effects of dietary CP concentration (160, 190 and 220 g/kg) and Thr supplemental concentration (0, 0.7, 1.4, 2.1 and 2.8 g/kg) on growth performance, carcass, liver lipid and plasma profiles were determined in Pekin ducks from 1–21 d of age.

2. A total of 720-d-old male Pekin ducks were randomly allotted to 1 of 15 dietary treatments with 6 replicate cages of 8 birds per cage for each treatment according to average body weight.

3. Dietary Thr supplementation improved growth performance and breast muscle percentage at all CP diets, and ducks fed Thr-supplemented diets had higher plasma concentrations of some plasma amino acids. Thr supplementation reduced the concentrations of total lipid, triglyceride, cholesterol in liver, and plasma low density lipoprotein cholesterin concentration at 160 and 190 g/kg CP, whereas it increased triglyceride concentration at 160 g/kg CP.

4. Thr requirements based on quadratic broken-line model estimation were 6.6 and 7.0 g/kg for optimal average daily gain (ADG), and 6.7 and 7.3 g/kg for breast muscle percentage of Pekin ducks from 1–21 d of age at 190 and 220 g/kg CP, respectively. The dietary Thr requirements and estimated ADG (55.18 vs. 55.86 g/d/bird) and breast muscle percentage (2.79% vs. 2.75%) of Pekin ducks did not differ between 190 and 220 g/kg CP according to the t-test results.

5. Dietary CP level could be reduced to 190 g/kg in Pekin ducks from 1–21 d of age with Thr supplementation to balance dietary amino acids, and Thr supplementation prevented excess liver lipid deposition in this instance.     

Influence of food intake and sex on the growth and carcase composition of Pekin ducks

1. The effects of food intake on growth and carcase composition of male and female meat‐type Pekin ducks were investigated between 14 and 56 d of age and between 0.416 kg (14 d) and 2.5 kg live body weight.

2. Males grew faster between 14 and 56 d of age and contained less fat and more protein and water in the eviscerated carcase at 56 d than females.

3. For both sexes, food : gain ratio deteriorated as food intake increased from 0.49 ad libitum intake to ad libitum intake. Growth rate, carcase weight and carcase fat content increased linearly with increase in food intake. Carcase fat content at 56 d was more sensitive to change in the amount of food consumed than either growth rate or carcase weight.

4. Between 0.42 kg (14 d) and 2.50 kg live body weight, growth rate and food :gain ratio improved as food intake was increased from 0.61 ad libitum to ad libitum. Males grew faster and produced leaner carcases than females.

5. Carcase fat content at 2.50 kg live body weight (1.60 kg carcase) increased in a curvilinear fashion with increase in food intake, and the magnitude of the response was lower for females than for males. A similar interaction existed between the effects of sex and the amount of food consumed for the proportions of protein and water in the eviscerated carcase at 2.50 kg live body weight.     

Rearing temperature and the meat yield of broilers

1. One hundred and twenty (60 male and 60 female) 21‐d‐old Ross 1 broiler chicks were reared in cages in rooms kept at 21°C or 31°C and were killed at body weights of 1.0, 1.5, 2.0, 2.5 or 3.0 kg.

2. Birds reared at either of the two temperatures ate similar quantities of food to reach their slaughter weight although at 31°C they took longer to reach it.

3. The meat yields of the birds at each slaughter weight were similar at both rearing temperatures, but at body weights greater than 2.0 kg, the broilers reared at 21 °C had more breast meat than those reared at 31°C.

4. Females ate more food than males to reach each of the slaughter weights. The females deposited more fat and had a greater skin weight than the males and, although they had a similar amount of total meat, they had more breast meat.     

Riboflavin requirements of white Pekin ducks from hatch to 21 d of age

1. A 2 × 8 factorial experiment containing different sexes (female and male) and 8 dietary riboflavin concentrations (1.2, 3.2, 5.2, 7.2, 9.2, 11.2, 13.2 and 15.2 mg/kg) was conducted to evaluate the riboflavin requirements of male and female White Pekin ducks from hatch to 21 d of age.

2. A total of 640 1-d-old Pekin ducks including 320 male and 320 female birds were randomly distributed into 80 wire-floor pens of 8 birds, sexed separately and with each treatment group containing 5 replicate pens. The birds were raised from hatch to 21 d of age. At 21 d of age, the weight gain, feed intake, feed conversion ratio and plasma and liver riboflavin were measured.

3. Growth depression, high mortality and low plasma and liver riboflavin were observed in riboflavin-deficient ducks, and these ill effects could be reduced by increasing dietary riboflavin concentrations. Weight gain, feed intake and riboflavin concentration in plasma and liver increased as dietary riboflavin increased.

4. According to broken-line regression analysis, the riboflavin requirements of modern breed of White Pekin ducks from hatch to 21 d of age for weight gain, feed conversion ratio, plasma riboflavin and liver riboflavin were 3.31, 5.20, 3.85 and 3.91 mg/kg for male and 3.27, 3.33, 3.84 and 3.28 mg/kg for female, respectively. Compared with female birds, more riboflavin was needed by male ducks, which may be because of significantly greater weight gain and liver riboflavin content of male ducks.     

Effects of selection,over three and four generations,on meat yield and fatness in Muscovy ducks

1. Two experiments were undertaken to analyse the effects of selection for lowering carcase fatness and improving meat yield of Muscovy ducks. The control generation N and the selected generations N+ 3 and N+ 4 of the same heavy line (Grimaud) were reared under similar conditions.

2. We compared growth, carcase characteristics, chemical composition of breasts and plasma concentrations of very low density lipoproteins (VLDL), triglycerides and phospholipids.

3. Selection induced an increase of body weight ( + 8% to 10% at slaughter age), a decrease of abdominal fat percentage (? 10%) and an improvement of breast and thigh plus shank yields (+ 3% to 7% and + 4% respectively).

4. The lipid content of breast meat decreased in the selected ducks (? 14% to ?20%), particularly phospholipids and triglycerides. Breasts appeared paler and less red which suggested modifications of muscular fibre composition.

5. We found no significant correlations between plasma VLDL, triglyceride and phospholipid concentrations and carcase fatness. It therefore seems difficult to use these variables as selection criteria for lowering carcase fatness of Muscovy ducklings.     

Effects of dietary probiotic supplementation on LXRα and CYP7α1 gene expression,liver enzyme activities and fat metabolism in ducks

1. The objective of this study was to investigate the effects of dietary probiotic supplementation on liver X receptor alpha (LXRα) and cholesterol 7α-hydroxylase (CYP7α1) mRNA levels, protein enzymatic activities and fat metabolism in Cherry Valley Pekin ducks.

2. A total of 750 one-day-old Cherry Valley Pekin ducks were randomly divided into 5 groups with three replicates of 50 ducks each in a completely randomised experiment. Each group was fed on a basal diet supplemented with 0, 500, 1000, 1500 or 2000 mg probiotics/kg.

3. Body rate and feed conversion ratio were highest and abdominal subcutaneous fat % was lowest at 1000 mg probiotic/kg.

4. The mRNA levels of LXRα and CYP7α1 in liver tissue was estimated by RT-PCR; serum triglyceride (TG) and total cholesterol (TC) concentrations were measured by ELISA.

5. The expression levels and enzyme activity of LXRα and CYP7α1 increased in conjunction with decreases in TG and TC concentrations following probiotic supplementation to a maximum at 1000 mg probiotics/kg and decreased thereafter.

6. It is concluded that dietary probiotics can enhance LXRα and CYP7α1 enzyme activities in the liver and reduce lipid concentrations and fat deposition in ducks.     

Environment and management factors affecting Pekin duck production and welfare on commercial farms in the UK

1.?Forty-six flocks of commercially-reared Pekin ducks were studied in 23 houses differing in their ventilation and brooding systems, and water and feed resources, in order to identify factors affecting duck welfare in commercial practice.

2.?A wide range of environmental variables were measured, together with the physical and plumage condition of the ducks at two ages, whilst companies supplied mortality and growth rate data.

3.?At 23 d, more than 98% of ducks had clean eyes, nostrils and feathers and an upright posture, and 86% had no gait abnormalities. By 41 d, body condition had deteriorated slightly with 84% of ducks having clean eyes, 67% clean feathers and 79% no gait abnormalities.

4.?Gait worsened with increasing temperature and litter moisture, and atmospheric ammonia concentrations. The incidence of foot pad lesions was 10% (moderate) and 3% (severe) and was positively correlated with increasing humidity and ammonia.

5.?Average mortality rates were 5?2% for ducks reared to 3?35 kg at 48 d with average growth rates of 60?3 to 81?3 g/d. High temperatures correlated with high mortality and reduced growth rate; growth rate was not related to poor gait.

6.?Controlling the ducks’ environment, particularly temperature, humidity, litter moisture and ammonia is crucial to duck welfare. Effective ventilation systems, high quality straw and access to some form of open water were considered important for duck welfare.     

Production traits of artificially and naturally hatched geese in intensive and free-range systems – II: slaughter,carcass and meat quality traits

1. This study investigates the slaughter, carcass and meat quality traits of artificially and naturally hatched geese in intensive and free-range production systems.

2. The study was conducted with 114 naturally hatched and 102 artificially hatched geese. From each replicate of the intensive and free-range systems, one female and one male goose were slaughtered at the ages of 14, 16 and 18 weeks (a total of 32 geese per slaughter week).

3. Artificially hatched geese had higher slaughter weights (5280 vs. 4404 g), carcass weights (3520 vs. 2863), dressing percentages (66.6–65.2% vs. 65.0–63.6%) and carcass part, feather and edible inner organ weights. The ratio of both edible inner organs and abdominal fat was higher in naturally hatched geese. Breast meat L*, a* and pH values and thigh meat dry matter values were higher in artificially hatched geese, whereas thigh meat b* and pH values were higher in naturally hatched geese.

4. Intensively reared geese had higher slaughter weights (4900 vs. 4783 g), carcass weights (3253 vs. 3130 g) and abdominal fat weights (280 vs. 250 g), as well as higher dressing percentages (66.3–64.9% vs. 65.3–63.9%). Breast meat b* and thigh meat L* values were higher in the intensive system, while breast and thigh pH values, dripping loss and cooking loss were higher in the free-range system. Water-holding capacity was higher in the intensive system.

5. In conclusion, artificially hatched, intensively reared geese had the highest slaughter weights; however, both artificially and naturally hatched geese raised in a free-range system reached acceptable slaughter weights and can thus be recommended for use with this type of production system.     

Physical and chemical properties of meat from scavenging chickens and helmeted guinea fowls in response to age and sex

1. The effects of age and sex on body weight, carcass traits, physical and chemical properties of breast muscle from chickens and helmeted guinea fowls managed under village free-range conditions were assessed in random samples of 48 guinea fowls and 48 chickens obtained from local markets.

2. Guinea fowls had higher body weight, hot carcass weight, cold dressed weight and breast weight than chickens.

3. Guinea fowls had more dry matter, protein and less fat than chickens. Ash content did not differ between guinea fowls and chickens. Protein and fat increased, whereas dry matter and ash decreased with age (P < 0.05)

4. Chicken meat was lighter, less red and more yellow than guinea fowl meat. Cooking loss was higher in guinea fowls, male and grower birds than chickens, females and adult birds, respectively. Shear force was affected by age, as mature birds had a higher value than growers.

5. Guinea fowl carcasses contained more meat that was leaner, higher in protein and redder compared with chicken meat. As age increased the meat increased in protein and fat content and shear force, whereas colour became darker, redder and yellower.     

Fat accumulation,fatty acids and melting point changes in broiler chick abdominal fat as affected by time of dietary fat feeding and slaughter age

1. This work aims to quantify changes in fatty acid profile, melting point, abdominal fat accumulation and 2-thiobarbituric acid-reactive substances production depending on dietary fat source and age at slaughter, and to estimate the optimal date for the change from an unsaturated fat to a saturated fat diet or vice versa.

2. Treatments established were (1) birds fed 8% tallow from 21 to 49 d (TTT); (2) birds fed 8% tallow from 21 to 37 d and 8% sunflower oil from d 38 to 49 (TSS); (3) birds fed 8% sunflower oil from 21 to 37 d and 8% tallow from d 38 to 49 (STT); (4) birds fed 8% sunflower oil from 21 to 41 d and 8% tallow from d 42 to 49 (SST); (5) birds fed 8% sunflower oil from 21 to 49 d (SSS). Birds from each group were slaughtered on d 21, 29, 38, 40, 42, 44, 46 and 49.

3. The polyunsaturated fatty acids (PUFAs) proportion in the SSS group reached maximum values at d 40 and fitted a quadratic response. This group also showed a decrease in saturated fatty acids (SATs) and monounsaturated fatty acids (MUFAs) of lower intensity than the PUFA increase. The highest synthesis of SAT + MUFA was found in the SSS and TSS groups, whereas these had the lowest body-to-dietary PUFA ratio.

4. A high and quadratic increase in the MUFA proportion was observed during the first 10 d of feeding with the tallow-enriched diet at the expenses of the proportion of PUFA that quadratically decreased (minimum values at d 38).

5. Lipogenic and desaturation capacity decreased with age.

6. The TSS group increased tissue PUFA content faster that the SST group decreased PUFA content after the change in diet which indicates that the earlier feeding has to be taken into consideration for obtaining higher or lower changes in quality parameters.

7. The melting point of the SSS group showed a lower response to the dietary treatment in the initial period when compared to the TTT treatment.

8. The TTT, STT, SST and TSS groups showed similar fat accumulation, and changes in lipid oxidation were related to the day of dietary sunflower oil supplementation.

9. Based on the results, it would be possible to determine the most appropriate dietary programme and optimum slaughter age to obtain chicken meat with the desired quality characteristics.     

Effects of dietary chromium chloride,nicotinic acid and copper sulphate on meat of broilers

1.?Combinations of chromium and copper were added to the diet to assess their effects on broiler meat characteristics.

2.?For this purpose 175 one-day-old broiler chicks were divided into 7 equal groups and were given treatment feeds containing copper sulphate, chromium chloride and nicotinic acid in different combinations.

3.?The study was carried out for 5 weeks and samples were collected at the end of 15, 29 and 35 d of treatment and at 42 d after a withdrawal period of one week.

4.?Cholesterol content had decreased significantly in breast meat at d 29 in all treatment groups. In thigh meat, it decreased significantly at d 29 in groups receiving two concentrations of chromium + two concentrations of copper. Cholesterol content remained lower even after withholding the treatment for one week.

5.?Crude fat content decreased significantly in breast meat in all treatment groups. In thigh meat, at d 29, a significant reduction in crude fat was observed only in birds receiving low chromium and high copper.

6.?Crude protein at d 29 increased significantly in breast meat of birds receiving low chromium and high copper, and low or high chromium, while it decreased significantly in treatment groups after withholding the treatment. In thigh meat, at d 29, it increased significantly in treatment groups but decreased significantly after withholding the treatment.

7.?It was concluded that chromium and copper, along with nicotinic acid, have modulating effects on broiler meat under tropical conditions.     

The effect of production system (barn and free-range), slaughtering age and gender on carcass traits and meat quality of partridges (Alectoris chukar)

1. A total of 400 Alectoris chukar partridges were reared in either barn or free-range production systems and slaughtered at 14, 16 or 18 weeks of age in order to determine the effects of production system, age and gender on carcass traits (live weight, carcass weight, carcass yield, carcass part and edible inner organ percentages at slaughtering) and meat quality (L*, a* and b* meat colour and pH).

2. Production system had a significant effect on both slaughter traits and meat quality.

3. Partridges raised in barn conditions had higher live weights and carcass weights whereas meat quality was better in birds raised in the free-range system.     

Effects of dietary supplementation of (β2‐adrenergic agonist clenbuterol on carcase characteristics and some metabolites in ducks

1. Ducks (622 in total) aged 25 d were given diets supplemented with clenbuterol (CL) at 0 (control), 0.5, 1, 2, 3 and 5 mg/kg for 25 d to investigate the effect of dietary CL on muscle and fat deposition and some metabolites in ducks.

2. The mass of the breast muscles was increased by 10 to 31%, while subcutaneous fat plus skin and abdominal fat pad were reduced by 8 to 23% and 20 to 37%, respectively, in the ducks supplemented 1 to 5 mg CL/kg diet.

3. Increased RNA:DNA ratios in the breast muscle, reduced uric acid and increased free fatty acid concentrations in the serum were observed in clenbuterol‐fed ducks.     

Comparative growth and development of the digestive organs and of some enzymes in broiler and egg type chicks after hatching

1. Body weight, the weight of digestive organs and activities of some digestive enzymes were determined from hatching to 14 d of age in meat‐ and egg‐type chickens.

2. Relative daily food intake and growth rate were much higher in meat‐than in egg‐type chickens. Relative daily food intake peaked at 30% of body weight at 3 d of age in meat‐type, and at 20% of body weight at 6 d of age in egg‐type chickens and then decreased gradually. The corresponding values for growth rate were 20 and 14%.

3. Allometric growth of the small intestine, intestinal contents and liver was greater in meat‐type chickens, but the growth of the pancreas attained a higher value in the egg‐type birds. Diminution of the vitelline residue was similar in the two breeds.

4. Pancreatic digestive enzyme activities were similar between stocks, but activities in the small intestinal contents were lower in meat‐type chickens.

5. The secretion of digestive enzymes in the newly‐hatched meat‐type chicken could be a limiting factor in digestion and, consequently, in food intake and growth.     

Carcase characteristics of quail (Coturnix coturnix japonica) slaughtered at different ages

1. The present study was conducted to evaluate the relationship between slaughter ages and carcase characteristics of Japanese quail.

2. Chicks were slaughtered at 5, 6, 7, 8 and 9 weeks of age. Carcase yield, carcase parts weight, weight of liver, heart, gizzard and alimentary tract were obtained. Protein, fat, dry matter and ash contents of meat were analysed for each sex.

3. Body weight and eviscerated weight were affected by age. Age had no significant effect on the weight of liver, alimentary tract, gizzard and heart. Age had first and second order polynomial effects on breast weight and relative leg weight. Meat compositions of leg and breast were significantly affected by age.     

Growth,food conversion,carcass yields and their heritabilities in ducks (anas platyrhynchos)

1. Live weight, food consumption, eviscerated carcass weight, breast muscle mass and ratios of these traits were measured in a strain of ducks of known pedigree. Heritabilities, genetic and phenotypic correlations were estimated for all traits. From the results the following conclusions are drawn.

2. Selection for live weight at market age would be simplest and most effective in improving growth rate and food conversion efficiency though would not necessarily markedly improve carcass lean meat.

3. Selection to increase the proportion of breast muscle (heritability (h ² ): 0.55) should be effective but might depress body weight as a correlated response. The effect on fat content is uncertain.

4. Selection for food conversion efficiency (h² : 0.21) might be expected to increase body weight, but its effect on carcass lean meat (proportion of breast muscle) is uncertain.

5. Selection for breast muscle mass (h ² : 0.41) should improve body weight and food conversion efficiency but its effect on proportion of lean meat is much less certain (rG = 0.45 + 0.17).