Susceptibility of various poultry species to dietary aflatoxin

1. The relative sensitivities of broiler chicks, White Leghorn chicks, quail chicks, goslings and turkey poults to increasing dietary contents of aflatoxin from 1 to 21 d of age were determined. Aflatoxin was included in the diets at three concentrations (0.7, 1.4 and 2.1 mg aflatoxin B_a equivalents /kg).

2. Data were analysed for species differences in food consumption, body weight, food utilisation, mortality and liver pathology.

3. There were no significant effects of aflatoxin in broiler and Leghorn chicks. Aflatoxin at 0.7 mg/kg decreased the body weight of turkey poults but tended to increase the growth rate of goslings. At 1 ‐4 mg aflatoxin/kg food consumption, body weight and weight gain of goslings were adversely affected.

4. Liver damage occurred in goslings and quail chicks at all inclusions of aflatoxin and was extensive at 2.1 mg/kg.

5. Poults and goslings appeared to be the most sensitive, quail were intermediate and domestic chicks were most resistant.     

Effects of nutrient concentration and dietary presentation on performance of dwarf hens

1. Diets containing 170 or 190 g protein/kg and 10.9 or 11.7 MJ ME/kg in all combinations were offered to dwarf hens in two dietary presentations: a complete mash or a form in which part of the protein and calcium contents were presented as soyabean meal pellets and limestone grit respectively.

2. Egg production and egg mass output were higher with the 190 g protein/kg diets.

3. Lower‐energy diets gave better egg production, while higher‐energy diets containing 190 g protein/kg improved food conversion efficiency.

4. Separation of protein and calcium constituents tended to give better egg production, food conversion efficiency, shell thickness and egg mass output.     

Effect of dietary protein content on live and carcase performance of heterozygous naked neck and normally feathered broilers

1. An experiment was conducted to determine the effect of different dietary protein contents on the performance of naked neck (Na/na) and normally feathered (na/na) broilers.

2. Chicks from the two genotypes were reared in wire‐floored cages and divided at random into 3 groups. Birds were fed on high protein (HP, 12.99 MJ ME, 238 g crude protein/kg and 12.94 MJ ME, 216 g crude protein/kg from 0 to 3 and 3 to 7 weeks, respectively), medium protein (MP, 12.99 MJ ME, 219 g crude protein/kg and 12.87 MJ ME, 201 g crude protein/kg from 0 to 3 and 3 to 7 weeks), and low protein (LP, 12.94 MJ ME, 205 g crude protein/kg and 12.75 MJ ME, 184 g protein/kg from 0 to 3 and 3 to 7 weeks) diets.

3. The LP diets resulted in a significantly lower daily body weight gain of males from 0 to 3 weeks. Dietary protein content had no effect on body weight gain from 3 to 7 weeks, body weight at 7 weeks, and the food intake of birds. Carcase composition of birds from both genotypes was unaffected by dietary protein.

4. Naked neck birds had significandy higher body weights at 7 weeks. Yields of carcase and breast of Na/na males were significantly higher than those of na/na males. There were no significant differences between females from the two genotypes as regards carcase yield.

5. It was concluded that the dietary protein requirements of naked neck birds were similar to those for normally feathered birds.     

Dietary selection of protein and energy by pullets and broilers

1. White Leghorn pullets and sexed broilers were allowed a free choice of two “ split‐diets “ which were concentrated sources of either crude protein (463 g/kg diet) or energy (13.32 to 14.00 MJ/kg diet).

2. Pullets receiving these two diets displayed a slower, but more uniform growth rate than did birds offered a single conventional diet. Up to 11 weeks of age, control birds consumed significantly more protein while the converse was true from 11 to 20 weeks. These differences are discussed in relation to the stage of sexual maturity.

3. Broilers offered the split‐diets grew more slowly and had an inferior food conversion ratio compared with control birds fed on a two‐stage rearing programme.

4. Among the broilers offered split‐diets, the usual sex differences were not observed for weight gain or carcass fat content.     

The performance of male ducklings given starter diets with different concentrations of energy and protein

1. Male ducklings were fed for 14, 21 or 28 d on diets containing 180, 200, 220 or 240 g of protein and 10.88 or 12.55 MJ of metabolisable energy (ME) per kg, followed by a common finisher diet until 56 d of age.

2. Birds given starter diets with 220 or 240 g of protein per kg were significantly heavier at 14 d than those given diets with 180 or 200 g protein per kg.

3. There was no significant benefit in feeding diets with protein levels greater than 180 g/kg for more than 14 d.

4. Diets with only 10.88 MJ of ME per kg produced significantly lighter birds at 28 and 56 d of age and significantly reduced food conversion efficiency up to 14 d.     

Sulphur amino acid requirement of laying hens and the effects of excess dietary methionine on laying performance

1. Individually‐caged laying hens were fed on maize‐soya bean meal diets containing 11.50 or 12.35 MJ ME/kg with sulphur amino acid (SAA) contents varying from 5.0 to 7.0 g/kg in period 1 (0 to 20 weeks); from 5.0 to 8.0 g/kg in period 2 (21 to 36 weeks) and from 5.0 to 10.0 g/kg in period 3 (37 to 52 weeks).

2. A SAA requirement of about 750 mg/hen d, of which about 425 mg was methionine, was found to be adequate for birds producing on average 51 g egg mass per hen d over 52 weeks. The SAA requirement was found to be higher for maximum efficiency of food utilisation than for maximum egg yield.

3. A diet containing 140 g protein/kg adequately supplemented with methionine and lysine, could sustain laying performance almost identical to that achieved on a diet containing 167 g protein/kg.

4. In diets with 140 g protein/kg the addition of 0.5 to 3.5 g dl‐methionine/kg diet in excess of the requirement did not affect egg production adversely, but food conversion efficiency was decreased.     

Replacing maize with sweet potato in diets for chicks

1. Rhode Island Red chicks and chicks of the indigenous fowl of Nigeria were fed for ten weeks on diets of 227.5 g protein and 11.92 to 13.72 MJ ME/kg in which sweet potato was substituted for maize.

2. Replacing up to 344.3 g maize/kg with sweet potato did not significantly affect body weight, food intake, food conversion, nitrogen retention, mortality and relative weights of body parts at 10 weeks of age.

3. Whereas crude protein contents of liver, gizzard, heart, lung and breast were not significantly affected by the diets, fat contents were significantly decreased by the replacement of 344–3 g maize/kg with sweet potato.     

The nutritional value of salseed (Shorea robusta) meal for growing chicks

1. Salseed meal contains 98 g crude protein, 22 g ether extractives, 450 g available carbohydrate and 117 g tannins per kg.

2. From the chemical analysis the metabolisable energy (ME) content of salseed meal would be expected to be 11.22 MJ/kg. In vivo assay with chicks yielded values considerably less than this, 7.1 MJ/kg being found at an inclusion rate of 150 g/kg diet.

3. As the inclusion rate of salseed meal was increased to 300 g/kg, dietary ME and the digestion and retention of dietary protein decreased.

4. More than 50 g salseed meal/kg in the diet of chicks resulted in poor growth rate and food conversion.     

Evaluation of methanol‐grown bacteria as a source of protein and energy for young chicks

1. The inclusion of 100 or 200 g/kg spray‐dried methanol‐grown bacteria in unpelleted semi‐purified diets reduced growth rate and efficiency of food conversion of young chicks over a 14 d period.

2. Classical metabolisable energy values for the spray‐dried product, at relatively low inclusion rates, ranged from 9.55 to 10.92 MJ/kg dry‐matter (DM) and nitrogen‐corrected values ranged from 8.95 to 10.16 MJ/kg DM.

3. Inclusion of 96 g/kg flash‐dried methanol‐grown bacteria in unpelleted semi‐purified diets marginally increased growth rates, efficiency of food conversion and nitrogen utilisation of chicks, but higher inclusions of up to 290 g/kg caused adverse effects.     

The protein and energy requirements of ducklings in the tropics

1. Protein and energy requirements of local and imported commercial strains of ducklings were determined under tropical conditions.

2. The results indicate a requirement for a diet with 240 g crude protein/kg, 9 g methionine plus cystine/kg and 12.97 MJ metabolisable energy/kg for maximum growth and food efficiency up to 8 weeks of age.

3. Though the imported commercial‐strain ducklings grew faster and utilised food more efficiently than the local strain, the general pattern of response indicated that optimum concentrations of nutrients were similar in the two strains.

4. The indicated nutrient contents are different from the recommended concentrations for ducklings in the temperate environment.     

The feeding of penicillin to goslings

A total of 180 crossbred Chinese/Emden goslings were either housed indoors for 8 weeks or kept inside for 4 weeks and then allowed to graze. Within each experimental group the birds were fed on diets with or without added penicillin. The antibiotic was included at either 55 mg/kg or 110 mg/kg.

Only when the goslings were fed throughout on a diet supplemented with penicillin at an inclusion rate of 110 mg/kg was there significant growth promotion.

No significant differences in the weights of the liver, gizzard, small intestine or caeca, or in the average weights of 1 cm lengths of the small intestines and caeca could be detected.     

Production traits of artificially and naturally hatched geese in intensive and free-range systems: I. Growth traits

1. This study investigated the effect of incubation type and production system on geese growth traits.

2. A total of 216 geese were either naturally (114) or artificially (102) hatched and reared in intensive or free-range production systems (4 replicates each) until 18 weeks of age.

3. Weights of naturally hatched goslings (NHG) were significantly higher than artificially hatched goslings (AHG) at 2 weeks (644 vs. 536 g); however, weights of AHG were significantly higher than NHG at both 6 weeks (3245 vs. 3010 g) and 18 weeks (5212 vs. 4353 g).

4. AHG had better feed conversion ratios (FCRs) than NHG (6.21 vs. 6.46 at 18 weeks). Feed consumption of naturally hatched geese was found higher in first 4 weeks when compared to artificially hatched geese and artificially hatched geese consumed more feed than naturally hatched geese after 8 weeks.

5. Production system had insignificant effects on feed consumption, FCRs, viability and mutilation rates.

6. Slipped wings were more frequent in NHG than AHG (8.32% vs. 1.68% at 6 weeks; 23.84% vs. 5.12% between 7 and 18 weeks) and in free-range production when compared to intensive production (17.88% vs. 11.08% over the course of the production period).

7. The study results indicate that both artificially and NHG can be reared in free-range production systems without any loss in performance and in deference to animal welfare.     

Calcium and phosphorus requirements of growing japanese quail

1. Calcium and phosphorus requirements of growing female Japanese quail during 4 and 5 weeks of age were estimated in a 4 × 3 factorial experiment comprising 5, 7, 9 and 11 g calcium and 5, 6 and 7 g phosphorus/kg diet.

2. Responses in weight gain, bone ash, food intake and food : gain ratio showed no significant differences due to varying dietary calcium and phosphorus concentrations.

3. It appears that growing Japanese quail require not more than 5 g calcium and not more than 5 g phosphorus (2 g available phosphorus)/kg diet (398 mg calcium and 398 mg phosphorus or 159 mg available phosphorus MJ ME).     

Energy,protein and limiting amino acid requirements of broilers at very high ambient temperature

1. Twenty one diets were formulated to contain three levels of energy (11.7, 12.5 and 13.4 MJ ME/kg), 4 levels of protein (starter 200, 220, 230 and 250 g, grower 180, 200, 220 and 240 g, and finisher 160, 180, 190 and 210 g/kg) and two concentrations of limiting amino acids (proportion of diet and proportion of protein) in each phase of growth, 0 to 3, 3 to 6 and 6 to 8 weeks of age. Each diet was fed to two pens of 15 broilers.

2. The house temperature ranged from 45°C to 51°C as maximum and 17°C to 22°C as minimum; the relative humidity ranged from 19 to 65.

3. Birds fed low energy (11.7 MJ/kg) and high protein (250, 240, 210 g/kg) diets with the National Research Council (1977) inclusion rates of lysine and sulphur amino acids in starting, growing and finishing phases of growth, attained significantly higher weight gains.

4. High energy, high protein (13.4 MJ/kg, 250, 240, 210 g/kg) diets gave greater efficiencies of food utilisation than low energy, low protein (11.7 MJ/kg, 200, 180, 160 g/kg) diets.     

Effects of high inclusion rates of salseed meal in the diet of chicks

1. Starter diets containing either maize or salseed meal to replace the maize were fed to chicks over a period of 2 weeks.

2. Growth rate, food intake, food utilisation and proportion of dietary nitrogen retained were much poorer in chicks receiving salseed meal.

3. The chicks receiving salseed meal developed pathological lesions in liver and kidney.

4. The red blood cell count, white blood cell count, haemoglobin concentration and packed cell volume of the chicks receiving salseed meal were lower than those of chicks receiving maize.

5. The apparent metabolisable energy value of salseed meal was determined as 6.83 MJ/kg.     

Effect of inclusion of sugar beet pulp,pelleting and season on laying hen performance

1. The effect of three metabolisable energy (ME) concentrations 12.2, 11.3 and 10.5 MJ ME/kg and two forms of diet (mash and pellet) on egg production in summer and winter were studied. The different ME values were obtained by diluting the 12.2 MJ ME/kg diet with sugar beet pulp of 2.88 MJ/kg DM. In a 3rd summer experiment the water intake of hens on these diets was examined. Data were analysed by factorial analysis of variance, and the relationship between performance and dietary energy concentration was examined by regression analysis.

2. The use of low energy diets (10.5 to 11.3 MJ ME/kg) decreased egg production in both seasons, but pelleting diets improved egg production and egg weight in summer. Egg weight was not affected by energy density in winter, but decreased in the summer when energy density increased.

3. In winter, food consumption was not affected by the dietary ME, while in summer food consumption increased when the dietary ME increased. Therefore, energy intake was not the same at all energy densities, but tended to increase as the energy density increased.

4. In summer, pelleting improved food efficiency and egg production and increased water consumption and the ratio of water to food intake. Water intake and water: food ratio decreased with increasing dietary energy concentration.     

Effects of different sources of dietary non-starch polysaccharides on the growth performance,development of digestive tract and activities of pancreatic enzymes in goslings

1.?The purpose of this study was to investigate the effects of different sources of dietary non-starch polysaccharides (NSP) on growth performance, development of gastrointestinal tract, and activities of pancreatic enzymes in goslings from 0 to 21 d of age.

2.?A total of 100 one-day-old White Roman female goslings were selected and randomly divided into 5 dietary treatment groups. Each group had 4 replicate cages (100 × 60 × 58 cm) of 5 goslings. Goslings in each group were given one of 5 isoenergetic and isonitrogenous semi-purified diets. Experimental diets were designed to contain 90 g/kg of different sources of dietary NSP from maize (control), barley hull, rice bran, wheat bran, or pectin, respectively, and 97·4 g/kg NSP were supplied by soybean meal.

3.?The goslings receiving the pectin diet had significantly higher viscosity in intestinal digesta than the other treatment diets. However, the daily feed intake, daily weight gain, and feed conversion ratio of goslings in the pectin group were significantly lower than those given the other diets.

4.?The relative weights of proventriculus, gizzard, liver and pancreas, as well as the relative weights and lengths of various intestinal segments in the goslings that received the pectin diet, were significantly higher than those receiving the other diets. The specific activities (SA) of amylase, lipase, trypsin, and chymotrypsin in the pancreatic tissue of goslings in the pectin group were significantly lower than those in the other groups.

5.?Goslings given a soluble NSP source (pectin) diet tended to exhibit inhibited growth and decreased activity of pancreatic enzymes. However, compared with maize, the inclusion of insoluble NSP sources from barley hull, rice bran, and wheat bran did not negatively affect growth and also were not significantly different among the treatment diets.     

The effects of dietary calcium concentration on pheasant breeder performance

1. Thirteen pens of breeding pheasants (Phasianus colchicus) were fed ad libitum on diets containing 20, 23 or 27 g calcium/kg.

2. All diets were formulated to contain 10.6 MJ ME/kg.

3. Three pens of birds receiving the diet containing 23 g calcium/kg were also offered grit free choice containing 280 g calcium/kg.

4. There were no effects of treatment on food consumption or reproductive performance.     

The effect on profit of Optimising nutrient density for laying hens

1. Using economic data from three locations in Australia nutrient densities were compared in laying diets which either minimised the daily cost of feeding a hen or maximised profit.

2. The effects of nutrient density on rate of production and egg weight were examined using published data to show that, within the range chosen for the analysis, nutrient density did not significantly (P < 0#lb05) affect rate of lay but was significantly and positively correlated (P< 0#lb01) with egg weight.

3. Nutrient densities which maximised profit were higher than those which minimised daily food cost.

4. Averaged over the three locations, maximum profit was achieved at a nutrient density of 11#lb80 MJ/kg compared with 11*57 MJ/kg to minimise food cost.

5. Food cost at the most profitable nutrient density was $2#lb00 per tonne higher than at the nutrient density which minimised food cost but resulting profit was slightly higher.     

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.