2. The Sinai produced significantly fewer, smaller eggs, resulting in lower egg mass output (g/bird d), than the Leghorn and the crossbreds.
3. Egg weight of both crossbreds was intermediate between Sinai and Leghorn but laying rate was closer to that of the Leghorn.
4. Differences in egg mass output apparent at 8 to 10 months of age decreased considerably with age.
5. These findings suggest that selection or crossbreeding of the Sinai might improve productive performance while maintaining improved eggshell quality. 相似文献
2. Egg weight was poor with the low fat basal diet but increased in relation to the amounts of maize oil (4 and 30 g/kg) included in the diet.
3. With a diet containing 30 g olive oil/kg, egg weight was similar to that obtained with the diet containing the same amount of maize oil.
4. Rearing the birds on diets containing low or moderate amounts of linoleic acid did not affect the response to fatty acid content of the layer's diet.
5. It is concluded that the requirement of the laying hen for linoleic add is not higher than 9 g/kg but that egg weight does respond to higher dietary amounts of readily absorbable fatty acids. 相似文献
2. During the last 7 years a random breeding sample of the production flock served as a genetic control.
3. Regressions of deviations of the production flock from the control flock on years, were highly significant for age at sexual maturity (‐2.18 d), egg production up to 275 d old (3.04 eggs), egg production to 500 d old (5.04 eggs) and egg weight at 14 months old (October) ( — 0.79 g).
4. The heritability of egg production up to 275 d old declined significantly from 0.35 to 0.19.
5. The realised heritability of egg production up to 275 d old was estimated to be 0.14.
6. The genetic correlation between egg production up to 275 d old and production in the residual part of the year was 0.48.
7. The rate of inbreeding in the production flock was 0.515% per generation and the expected rate of inbreeding in the control flock 0.21% per generation. 相似文献
2. The ileal endogenous amino acid losses were markedly higher (P< 0–001) in birds given the cottonseed meal diet compared to those given the other two diets. The ileal endogenous protein was rich in aspartic acid, serine and glutamic acid.
3. Negative values were obtained for endogenous amino acid output in excreta. These aberrant values were caused by high concentrations of homoarginine in the excreta. A subsequent study with broiler chickens showed that the homoarginine in excreta was of urinary origin.
4. These results indicate that the homoarginine technique is not suitable for determining endogenous amino acid losses in excreta, but applicable when determinations are made in the terminal ileum. 相似文献
2. At Ta 32 °G there was no panting. At Ta 35 °G panting occurred without any increase in Tr but there was a slight alkalosis (pH 7.55).
3. At Ta 38 °G Tr increased and panting was accompanied by moderate alkalosis (pH 7.58).
4. At Ta 41 °G Tr increased considerably and severe alkalosis developed (pH 7.65).
5. From the relation between Tr , f and pH it is concluded that some degree of alkalosis is a normal response to panting in the laying hen. 相似文献
Restriction of feeding to a 40‐min period, 105 min before sampling, significantly increased total plasma amino acid levels (P< 0.05) and individual concentrations of serine and proline (P<0.05) and glycine (P<0.01). The cause of these changes is not clear. Amino acid concentrations in samples taken at different times during the day were fairly constant. In the sampling procedure adopted routinely, birds were allowed free access to their diets for two weeks and sampled at 14.00 h on day 14.
The effect of dietary lysine level, at two protein concentrations, on plasma amino acid levels was evaluated. With inadequate and excessive dietary lysine concentrations total plasma amino acid levels were generally elevated. Plasma levels were least with diets containing 0.9 to 1.15% lysine.
The lysine requirements for optimum performance measured by growth rate, food conversion efficiency and nitrogen retention were identified as 1.2% with a 21% protein diet and approximately o‐8% with a 16% protein diet. The data indicate that efficient utilisation of dietary protein and relatively low levels of amino acids in the plasma are fairly closely related. 相似文献
2. Ultracentrifuge experiments at 2.7 × 105 g gave values of s 20, W = (1.49 + 0.16C) × 10?13 s for the sedimentation coefficient and D20 w = (1.12 + 0.19c) × 10?6 cm2 s?1 for the diffusion coefficient, c being the protein concentration (g/100 ml).
3. According to the Svedberg equation, these imply a molecular weight of 12,470 daltons, assuming [v_bar] = 0.74 ml/g.
4. Using refractometer measurements of protein concentration it was found that E 1% 1cm (278 nm) = 5.57 at pH 7.8.
5. From the ultraviolet absorption spectrum of the protein in 0.1 N NaOH it was concluded that the molecule probably contains four tyrosine residues and no tryptophan.
6. On this basis a revised amino acid composition is given. 相似文献
2. Bidirectional selection, based upon sire‐family means, was made over a single generation using egg breakage rate as the basis of selection: significant differences were obtained after one generation.
3. Heritability of the rate of egg breakage was estimated as 0.48 + 0.05. 相似文献
2. Egg outputs for White Leghorns fed ad libitum or restricted by 11 or 15% in energy intake were 48.lb3, 51.lb0 or 47.lb9 g/d respectively. 相似文献
2. Lipoxygenase was not involved in this phenomenon since addition of linoleic acid to the diets containing field beans did not improve egg weight.
3. The depressing effect of the field beans was proportional to the proanthocyanidine content of the seed extracted with absolute methanol.
4. In a longer trial (252d) field beans rich in these kinds of tannin decreased laying rate, efficiency of food utilisation and tended to increase mortality.
5. The removal of the hulls from the field beans did not prevent the reduction in egg weight. 相似文献
2. The production of double‐yolked eggs/100 hen d, high during the initial weeks of lay, rapidly declined and disappeared by 30 weeks of age.
3. The frequencies of broken, membranous and soft‐shelled eggs were significantly correlated with each other and with the frequency of multiple daily ovulations indicating a common aetiology for these defective egg types.
4. Double‐yolked eggs were produced by the heavier, earlier‐maturing pullets in the population.
5. Normal egg production in dwarf White Leghorns may be enhanced by reducing the incidence of defective eggs. 相似文献
A low‐Mn diet depressed the glucosamine content of isthmus and uterus but had no effect on galactosamine nor hydroxyproline.
The contents of hexosamine were similar after 3 months of egg production to those at the start of lay, and hexosamine and hydroxyproline values did not differ whether a non‐calcified egg was in the isthmus or one with an almost fully formed shell was in the uterus.
The glucosamine content of the isthmus was significantly greater than that of the uterus; the reverse was found for hydroxyproline and there was no difference between the galactosamine contents. In tissue from both regions the concentrations of glucosamine was several times greater than that of galactosamine. 相似文献
2. Response experiments involving the amino acids methionine, lysine and isoleucine were conducted, in each case at three dietary energy concentrations, using a diet dilution and blending technique, thereby ensuring a constant ratio between background amino acids and the first‐limiting amino acid in all diets, and also keeping the ratio of amino acids to energy constant as energy varied.
3. A common response curve relating egg output (g/bird d) to amino acid intake (mg/bird d) for each amino acid, fitted by means of the Reading Model, adequately described the response at each of the dietary energy contents. This implies that energy does not influence egg output directly, but only indirectly through its effect on food intake and hence on amino acid intake.
4. Both amino acid and energy concentration significantly influenced food intake. Energy intake was not constant over all dietary energy concentrations, being lower at low energy levels and higher at high energy concentrations.
5. It is concluded that amino acid requirements should not be stated either as percentages or as ratios with energy. Optimum amino acid intakes and energy concentrations should be calculated; the expected food intake should then be predicted, after which the appropriate concentration of nutrients in the diet can be determined. 相似文献
2. Body‐weight gain and carcass fat and water content increased and fertility decreased with increasing energy allowance. Maximum egg production occurred at an energy intake of 1.73 MJ AME/bird d.
3. Differences in egg weight and hatchability were related to differences in both energy and protein intake. The highest egg weight occurred at the highest allowance of energy and protein. Hatchability was depressed where the daily allowances of protein and energy were in a ratio of more than 15 g protein: 1 MJ AME.
4. Apart from egg size no significant effects on reproductive performance were observed when dietary protein intake was varied from 27 to 19.5 g/bird d.
5. Requirements of broiler breeder hens for protein during lay may be lower than previously thought. For the strain used a protein intake of 19.5 g/bird d appeared adequate provided essential amino acid concentrations were maintained.
6. The close relationships between body weight and energy allowance and the latter and egg production make body‐weight gain a useful guide to management. A body‐weight gain of about 1.1 kg from 21 to 36 weeks of age was associated with optimum performance in this study. 相似文献
It has been found that (a) the age of the egg considerably influences both the formation of artificial translucence and the strength of the shell, (b) the less rigid the shell, the smaller is the force required to produce artificial translucence, and (c) the greater the force, the greater the width of the translucent area. These findings point to shell damage as the cause of artificial translucence and a system of cracks in the shell has been found to be associated with the translucence.
The results have been discussed in the light of the composite structure of the egg shell. 相似文献
2. In the first experiment, 144 pullets, 72 each of Ff and ff pullets from F1 birds, were compared in a randomised complete block design (RCBD), with three villages and 4 batches of hatch as blocks and the two feather genotypes (Ff and ff) as the treatments.
3. The Ff pullets were superior (P < 0.05) to their ff counterparts in terms of the number of eggs per clutch, egg mass and hen-housed and hen-d rates of lay, whereas age at first egg was lower (P < 0.05) in ff layers compared to Ff ones.
4. The eggs of the F1 heterozygous frizzle (Ff) layers had higher values for albumen height, Haugh unit and yolk height compared with eggs from their normal feathered counterparts.
5. In the second experiment, 144 pullets, 48 each of FF, Ff and ff pullets, were compared in a RCBD, with three villages and 4 batches of hatch as blocks and the two feather genotypes (Ff and ff) as the treatments.
6. The F2 birds with genotypes Ff and FF were better than their ff counterparts in terms of the number of eggs per clutch, egg mass, and hen-housed and hen-d rates of lay. Age at first egg was significantly lower in ff layers compared to FF and Ff ones.
7. The Haugh unit value was higher in the homozygous and heterozygous frizzles compared to the normal feathered ones.
8. The presence of the frizzle gene (F) in egg type chickens led to an improvement in egg production and egg quality traits in village chickens, and the cross-breeding scheme evaluated in this project could contribute to improved productivity. 相似文献
2. The shell thickness increased and the area density of pores decreased from the blunt to the pointed end of the egg. During incubation, shell thickness decreased, but the shell diffusive conductance to water vapour (GH2O) remained constant.
3. Fresh egg mass (m0), length and breadth of the egg, GH2O and specific water vapour conductance, spGH2O (GH2O per g of m0 ), were affected by the age of the laying flock.
4. Eggs of the domestic guinea fowl were bigger and heavier than eggs of the wild one.
5. Allometry showed that guinea fowl eggs differ from those of the other birds by their greater shell thickness and density of pores. However spGH2O was normal, the thickness of the shell being compensated for by a greater density of pores for gas exchanges. 相似文献
2. Tissue residue profiles (liver, kidney, lung and muscle) and plasma were also studied after multiple intramuscular and oral administrations of 5 mg/kg body weight, once daily for 5 consecutive days.
3. Following intravenous injection, plasma concentration–time curves were best described by a two-compartment open model.
4. After intramuscular and oral administration of moxifloxacin, the peak plasma concentrations (Cmax) were 2.14 and 1.94 μg/ml and were obtained at 1.40 and 1.87 h (Tmax), post administration, respectively.
5. The systemic bioavailabilities following intramuscular and oral administration, respectively, of moxifloxacin were 92.48 and 87.94%.
6. Tissue concentrations following i.m. and p.o. administration were highest in liver and kidney, respectively, and decreased in the following order: plasma, lung and muscle. No moxifloxacin residues were detected in tissues and plasma after 120 h after i.m. or oral administration. 相似文献