Effects of breeder hen age and dietary L-carnitine on progeny embryogenesis

1. Ross 308 broiler breeder hens were given diets containing 0 or 25 mg L-carnitine/kg (8 replications per treatment) from 21 weeks of age. 2. Hens were inseminated with semen from Ross broiler breeder males. In a common facility, subsequent progeny hatchability and embryonic mortality at 25, 30, 32, and 38 weeks of breeder age were evaluated. 3. Subsequent egg component weights, incubational egg water loss, progeny embryo growth, and embryo, yolk sac and liver composition through 18 d of incubation at 27, 32, and 38 weeks of breeder age were evaluated. 4. Calculated additions of L-carnitine were in agreement with analysed contents of 3.5 and 31.1 mg free L-carnitine/kg of diet, respectively, and total L-carnitine concentrations increased by 48.6, 21.7, and 10.0% in 0-d yolk, 18-d yolk sac, and 18-d liver samples, respectively, due to the addition of dietary L-carnitine. 5. Supplemental L-carnitine resulted in increased (0.6%) relative 0-d egg yolk weight across weeks 27, 32, and 38, and reduced (0.38%) 18-d yolk sac palmitoleic acid concentration at week 27 without altering embryogenesis. 6. In conclusion, dietary L-carnitine (25 mg/kg of the diet) was deposited in the yolks of broiler breeder hens and was subsequently transferred to the embryonic liver via yolk sac absorption through 18 d of incubation. Furthermore, dietary L-carnitine supplementation increased ovarian follicle yolk deposition in 27-, 32-, and 38-week-old breeder hens, and influenced yolk sac fatty acid beta-oxidation in embryos from 27-week-old breeder hens causing yolk sac palmitoleic acid concentrations to be reduced by 18 d of incubation.     

Teratogenic activity of Arasan fed to broiler breeder hens.

Tetramethylthiuramdisulfide (TMTD), the active ingredient in Arasan, fed to broiler breeder hens at 10, 20, or 40 ppm depressed egg production, reduced hatchability, and resulted in soft-shelled eggs. The progeny of these hens had anomalies manifested by bilaternal medial deviation of the toes, exophthalmia, and shortened femurs. Broiler breeder hens that consumed a ration containing 80 ppm of TMTD produced only soft-shelled eggs.     

Effect of a live reovirus vaccine on reproductive performance of broiler breeder hens and development of viral tenosynovitis in progeny.

A live commercial reovirus vaccine, Enterovax, was administered to adult broiler breeder hens via the drinking water to determine its efficacy in stimulation of circulating antibody. This vaccine was compared with a commercial inactivated reovirus vaccine. Only the inactivated product resulted in increased antibody as measured by a commercial enzyme-linked immunosorbent assay. However, the live reovirus vaccine caused diarrhea in the hens and decreased eggshell quality, fertility, and hatchability. In addition, the live vaccine virus was vertically transmitted from hens to their progeny, resulting in increased embryonic mortality and viral tenosynovitis.     

The effect of maternal vitamin D source on broiler hatching egg quality,hatchability, and progeny bone mineral density and performance

Vitamin D is involved in calcium metabolism as well as bone and shell quality, and is therefore important to broiler breeders. In this research we investigated the effects of maternal dietary 25-OH vitamin D₃ on broiler breeder egg quality and hatchability, as well as on progeny bone mineral density and performance. In a field study, all hens were fed 3,000 IU of vitamin D₃ (D) per kilogram of complete feed; in addition half of the hens also received 34.5 µg of 25-OH vitamin D₃ per liter in the drinking water (25OHD). Eggs from each treatment group were incubated and hatched; chicks were fed a common diet and grown to 41 d of age. Eggs from hens in the 25OHD treatment had a nearly 30% reduction in early embryo mortality. However, a larger egg size resulted in greater chick BW for the D chicks, although this did not affect broiler production performance. Broilers from the maternal 25OHD treatment had a lower FCR during the grower phase. Unexpectedly, chick plasma 25-OH vitamin D₃ was only greater for the maternal 25OHD treatment at 4 d of age, but not at hatch, 2, 6, 8, 10, 12, or 14 d of age. Maternal vitamin D₃ source did not affect progeny 41-d bone mineral density. Maternal 25-OH vitamin D₃ had a protective effect on the growing embryo, reducing early embryonic mortality, with minimal effects on progeny performance and bone mineral density to processing at 41 d of age. The previously reported effects of 25-OH vitamin D₃ on increasing broiler performance and breast yield seem to be dependent on supplementation of the broiler diet; a carry-over effect of maternal supplementation is insufficient to achieve these effects.     

Eggshell conductance,embryonic growth,hatchability and embryonic mortality of broiler breeder eggs dipped into ascorbic acid solution

1. Eggs from a broiler breeder flock between 25 and 29 weeks of age were dipped into solutions of various concentrations of ascorbic acid (AA) for up to 2 min, in order to evaluate its effects on eggshell conductance (EC), amniotic fluid pH, albumen height and pH, embryonic weight and hatchability. 2. Three experiments were conducted and the following treatments were used: control, non-dipped (CND); control, water-dipped (CWD); 10 g AA/l (AA1); 20 g AA/l (AA2) and 30 g AA/l (AA3). Measurements of EC before and after dipping were made in experiments 1 and 2 in eggs from hens at 25 and 27 weeks of age, respectively. Albumen height and pH were measured after dipping the eggs in experiment 2. In experiment 3, egg weight loss, embryonic weight and amniotic fluid pH at 14 d of age, hatchability percentage (HP), and embryonic mortality were measured in eggs from hens at 29 weeks of age. 3. AA treatment of eggs and dipping period of time (1, 1.5 and 2 min) increased EC of eggs from hens at 25 and 27 weeks of age. 4. AA3 treatment for 2 min reduced albumen height and increased albumen pH of eggs when compared with the CND treatment in eggs from hens at 27 weeks of age. 5. HP of AA1-treated eggs from hens at 29 weeks of age was higher than that of the CND treatment. AA2 and AA3 treatments of eggs reduced HP and increased the percentage of non-pips when compared with any of the other treatments. 6. AA2 and AA3 treatments of eggs increased egg weight loss when compared with the control treatments (CND and CWD). Dipping treatment did not influence amniotic fluid pH or embryo weight expressed as a percentage of initial egg weight. 7. It is concluded that dipping hatching eggs into AA solution increased EC of eggs. Dipping eggs into 10 g AA/l for a period of 2 min increased HP in eggs from hens at 29 weeks of age, although this was not associated with a significant increase in egg weight loss.     

Effects of ad libitum feeding on performance of different strains of broiler breeders

(1) Tolerance to ad libitum feeding was compared in three genotypes of broiler breeder hens: a standard broiler breeder fed ad libitum (SA) or restricted (SR), a slow growing 'label' broiler breeder (L) and an experimental dwarf heavy broiler breeder (E). Two similar experiments were conducted in two distinct research centres. (2) Feed intake and body weight were measured every 3 weeks from hatch to 40 to 49 weeks of age. Egg production and egg abnormalities were recorded. The number of yellow follicles in ovaries was counted at the age of 32 weeks. (3) Body weight was stabilised at 2.2, 3.7 and 5.4 kg after 24 weeks of age in L, E and SA hens, respectively. Growth of the SR hens was similar to that of L up to 20 weeks and stabilised at a similar level to that of E hens after 30 weeks of age. (4) Sexual maturity was delayed by 6 weeks in restricted breeders compared to ad libitum fed hens that started to lay at 20 weeks. SA hens had low egg production and a high proportion of defective eggs, which was largely compensated for by feed restriction. However, productivity of SR hens remained lower than that of L breeders. (5) Compared to the low viability and reproductive fitness observed with SA hens, the E dwarf broiler breeder tolerated ad libitum feeding and had better egg production, fewer egg abnormalities and yellow follicles per ovary and a higher egg production. However, laying rate was still lower than that of the SR and L groups. Energy conversion (kJ/g egg) from 32 to 40 weeks of age was much higher in the SA group than in the other three groups. 6. The feasibility of feeding a dwarf broiler breeder ad libitum calls for further research on implications of specific IGF and GH-receptor expression at the level of the ovary in dw chickens.     

The effect of palm oil and safflower oil in the feed of parent fattening hens on fertility, hatchability and growth of progeny]

The aim of two experiments with broiler breeder hens was to evaluate the effect of diets containing palm butter or safflower oil (25 g and 50 g/kg feed, resp.) on fertility, hatchability and growth of progeny. Especially the incorporation of oleic and linoleic acid in egg yolk reflected the dietary fatty acid source. Eggs were collected and stored in the incubator at a hen age of 31, 40, 50, and 60 weeks. Hatched chicks were reared over 5 weeks. The number of fertile eggs (Experiment 1 and 2, 75 and 88%, resp.) differed between the experiments (P < or = 0.05). Neither embryonic mortality nor hatchability (Experiment 1 and 2, 76 and 78%, resp.) were significantly affected by fatty acid composition of yolk. No clear maternal dietary effect was recorded on chicken weight at hatching (Experiment 1 and 2, 43.3 g and 43.7 g, resp.) and at 35 days of age (Experimental 1 and 2, 1676 g and 1764 g, resp.) The fatty acid composition in the analysed egg yolk sac of chicks showed a different fatty level but corresponded to fatty acid composition of breeding eggs before incubation. According to a decreased level of docosahexaenoic acid in egg yolk due to increased incorporation of linoleic acid, the content of this fatty acid was also diminished in phospholipids of the brain of chicken on days 1 and 5 after hatching.     

Cassava root chips andMoringa oleifera leaf meal as alternative feed ingredients in the layer ration

A study was conducted to evaluate effects of cassava root chips (CRC) andMoringa oleifera leaf meal (MOLM) inclusion in layer rations on egg laying performance, egg quality parameters, fertility, and hatchability. One hundred twenty Dominant CZ layers, 22 wk of age, and 12 cocks were used and equally divided into 4 dietary treatments with 3 replications. Treatment rations contained CRC and MOLM [i.e., T₁ (0% CRC and 0% MOLM), T₂ (50% CRC and 0% MOLM), T₃ (0% CRC and 5% MOLM), and T₄ (50% CRC and 5% MOLM)]. The CRC and MOLM were used to substitute for 100% corn grain and 5% soybean meal, respectively. Hens were weighed at the start and end of the experiment and BW change was calculated. Data on DM intake, hen-day egg production, egg weight, and egg mass were recorded daily. Egg quality parameters were determined at an interval of 15 d on 4 eggs per replicate. Fertility and hatchability of eggs, as well as mortality of birds and embryonic mortality of fertile eggs during the incubation period were recorded. From the chemical analysis, the calculated ME content of CRC was 3,852 kcal/kg of DM and the CP content of MOLM was 28%. The DM intake of birds, hen-day egg production, egg mass, FE, and mortality rate were not influenced by treatments. Body weight change and egg weight were higher for T₄ as compared with other treatments. Most external and internal egg quality parameters, especially yolk color, were improved when the diet contained MOLM. Fertility showed nonsignificant differences among treatments. However, hatchability percentage for T₁ was lower than the other treatments. In conclusion, CRC at 50% of the diet, CRC replacing corn grain 100%, or MOLM at 5% of the diet replacing soybean meal can impart similar or better positive effects on egg production, egg quality parameters, eggs fertility, and hatchability of Dominant CZ layers. Thus, 50% CRC, 5% MOLM, or a combination of both can successfully be used in the diet of layers as energy and protein feed ingredients, respectively.     

Effect of intensity of eggshell pigment and illuminated incubation on hatchability of brown eggs

The effects of intensity of brown eggshell pigment (light (LBP), medium (MBP) and dark (DBP)) and light intensity during incubation (low and high, 900 to 1380 and 1430 to 2080 lux, respectively) on eggshell characteristics, embryonic growth, hatchability traits, chick hatching weight and hatching time were investigated using eggs from a meat-type breeder (Hybro) flock at 32, 36 and 41 weeks of age in three trials. With eggs of similar weights the intensity of brown pigment was not associated with eggshell weight and thickness, and did not influence embryo weight and egg weight loss during incubation. The shade of brown pigment of eggs laid by young hens influenced the percentage hatchability (HP) of eggs incubated under light. Illuminated incubation improved HP of LBP eggs (compared with MBP and DBP eggs) from 32- and 36-week-old hens, but had no significant effect on HP of eggs from 41-week-old hens. Light intensity during incubation did not influence egg weight loss. High intensity of light during incubation reduced HP and increased early death percentage (EDP) in the LBP and MBP groups, and did not influence HP and EDP in the DBP group. Brown eggshell pigment and intensity of light during incubation did not influence hatching time. It is concluded that the shade of brown pigment, intensity of light during incubation and age of the breeder hens influenced the hatchability performance of embryos from brown eggs. Light during incubation improved the hatchability of embryos in light brown eggs laid by young hens and the shade of brown pigment of eggs laid by older hens did not influence hatchability under illuminated incubation. High intensity of light during incubation reduced hatchability of light and medium brown eggs, but not the dark brown eggs.     

Feeding motivation on the incidence of floor eggs and extraneously calcified eggs laid by broiler breeder hens

1. Commercial broiler breeder hens lay many eggs on the floor rather than in nest boxes provided. A study was conducted to determine whether feeding feed-restricted broiler breeder hens during the sitting phase of nesting results in a higher incidence of floor eggs and/or retained eggs. 2. Sixty broiler breeder females (Ross 308) were randomly assigned to 6 deep litter pens containing 10 nest-boxes. At 35 weeks of age and for 9 weeks, feed was distributed to all pens at lights-on every second day (fed normally, FN). On alternate days (feeding delay, FD), feed was distributed when 2-3 hens/pen were sitting in a nest box. Behaviour was sampled at 41 weeks of age, for 26 d. Eggs and egg location data were collected daily, and eggs were scored for extra-cuticular calcium. 3. Of 81 instances in which the hen was sitting firmly in a nest box at the time of feeding, on 80 instances the hen left the nest-box to feed, and on one instance the hen laid her egg then exited to the feeder. Of these 80 instances, on 58 occasions the hen returned to a nest-box to lay her egg; on 12 the hen returned to the nest-box but laid no egg; on 7 the hen did not return to the nest box and laid no egg; and on three the hen laid her egg on the floor. 4. Mean floor egg percentage was 13·3 ± 3·2% on FN and 13·3 ± 4·7% on FD days; these did not differ significantly. 5. The mean extra-cuticular calcium score over all pens was 0·9 ± 0·06 on FN days and 1·2 ± 0·06 on FD days; these differed significantly. 6. In conclusion, feeding broiler breeder hens during nesting results in a conflict between feeding and nesting motivation and higher numbers of extraneously calcified eggs, but does not result in a significant increase in floor eggs even though nesting hens will leave the nest box for food.     

Influence of the dwarfing gene dw on egg production and viability under summer heat stress

1. Dwarf egg layer (Narmada XL) dwarf broiler (DB) and normal bodied sib (NB) hens were studied under cyclic summer hot and dry heat stress of 21.1 to 45.5 degrees C for a period of 50 d. The genotype effect for egg production was significant (P less than 0.01). 2. N-XL and DB genotypes laid 12.1% more eggs than NB. Egg production declined by 3.17, 1.27 and 3.25% for a rise in temperature (maximum) of 1 degree C for N-XL, DB and NB genotypes respectively. 3. Egg production in Narmada XL declined by 42% compared to 25% in the dwarf broilers. The regression coefficients differed significantly. 4. For polygenically identical DB and NB broiler breeder hens the heat stressor significantly reduced egg production 1.98% more in the NB genotype compared with DB with a 1 degree C rise in temperature. 5. Mortality was less in the N-XL as compared to DB, but NB hens showed 11.7% more mortality than dwarfs.     

Identification of critical periods for turning broiler hatching eggs during incubation

(1) Fertile hatchability was superior from a broiler breeder flock at 29 weeks of age than at 68 weeks of age because of decreased mortality at all stages of embryo development. (2) Eggs that were either turned or not turned during the 0 to 7 d, 8 to 14 d and 15 to 18 d periods in the 8 possible combinations showed that the absence of turning from 0 to 7 d of incubation caused a decrease in fertile hatchability and an increase in all stages of embryonic mortality, and an incidence of Malposition II (head in small end of shell) that was more pronounced in a 68-week-old flock than a 29-week-old flock. (3) When eggs from 33- and 35-week-old broiler breeder flocks were either turned or not turned from 0 to 2 d, 3 to 4 d, 5 to 6 d or 7 to 8 d in the 16 possible combinations, the absence of turning from 3 to 8 d, or 0 to 2 d alone or in combination with other time periods reduced fertile hatchability and increased embryonic mortality and percentage of Malposition II. (4) The most critical period for turning commercial broiler hatching eggs during incubation was from 0 to 7 d with the single most critical 2-d period being 0 to 2 d.     

Effect of prolonged heat stress in single-comb white leghorn hens on progeny resistance to Salmonella enteritidis organ invasion.

In our laboratory, we have often had difficulty infecting neonatal chickens with invasive salmonellae when ambient temperatures exceed 30 C. We hypothesized that this increased resistance in chicks during warmer months may be associated with heat stress-associated maternal factors. Presently, single-comb white leghorn hens were separated into a non-heat-stressed group, reared under temperatures from approximately 10 to 24 C, and a heat-stressed group, in which environmental temperature was incrementally elevated to near 37 C and maintained for the duration of the 13-wk study. For Expt. 1, eggs from heat-stressed or control hens, collected on days 8-14 of the study, were pooled respective to treatment and incubated. At the time of egg collection, mean hen-day egg production was 51.83% or 65% for heat-stressed or control hens, respectively. On day of hatch, progeny from hens in each group were orally challenged with 0.9 x 10(4) colony-forming units (CFU) Salmonella enteritidis (SE). Rates of SE organ invasion of 97.3% or 94.4% were obtained in progeny from heat-stressed or control hens, respectively. In Expt. 2, eggs from heat-stressed or control hens from days 30-42 of the study were collected and pooled by treatment for incubation. Mean hen-day egg production was 46.5% or 72.85% for heat-stressed or control hens, respectively. On day of hatch, progeny were orally challenged with either 2.2 x 10(3) or 2.2 x 10(4) CFU SE. A 100% incidence in SE organ invasion was observed in all groups. In Expt. 3, eggs were collected from days 43 through 56 of the study. Mean hen-day egg production was 19.8% or 76.8% for heat-stressed or control hens, respectively. On day of hatch, progeny were orally challenged with 2 x 10(3) CFU SE. Rates of SE organ invasion of 95.8% or 95.6% were obtained in progeny from heat-stressed or control hens, respectively. These data suggest that factors other than elevated temperature may be responsible for seasonal resistance to invasive salmonellae infection in neonatal chickens observed in our laboratory during warmer months in Texas.     

Stability of dietary ascorbic acid and the effect of supplementation on reproductive performance of broiler breeder chickens

1. The purpose of the study was to determine the stability of dietary ascorbic acid and the reproductive responses of broiler breeder chickens to supplemental 75 mg ascorbic acid/kg diet. 2. Six breeder flocks of 13,000 birds each were studied. Egg production, eggshell porosity, fertility, hatchability and plasma ascorbic acid were measured. 3. Storage of the diets under dry heat resulted in a linear decrease in ascorbic acid content and the rate of decline was 5-fold higher in the supplemented diet. 4. Differences were not detected between treatments in egg production, egg weight, eggshell porosity, fertility, hatchability or plasma ascorbic acid. 5. The results did not provide evidence of a beneficial reproductive response to the inclusion of ascorbic acid in commercial broiler breeder diets.     

Effects of Microbial Phytase Supplementation on Egg Production and Egg Quality in Hy-line Brown Hens During the Late Laying Period

The objective of this study was to evaluate the effects of microbial phytase on egg production and egg quality in older hens. A total of 216, 63-week-old Hy-line brown laying hens were distributed in a randomized complete design 10-week feeding trial of 3 dietary treatments with 12 replications per treatment and 6 hens per replication. The 3 dietary treatments were corn-soybean meal-based diets supplemented with 0% (CON), 0.06% (TRT1), and 0.12% (TRT2) microbial phytase. Significantly higher hen-day egg production was observed in the TRT1 treatment compared to CON (P<0.05), except during the first two weeks of the experiment. During weeks 3, 4, and 9, TRT2 had a greater hen-day egg production percentage than CON (P<0.05). The damaged egg ratio was not affected. The egg quality parameters (e.g., eggshell color, eggshell strength, albumen height, egg weight, and the Haugh unit) were affected by microbial phytase supplementation (P<0.05). However, there were no significant effects on the eggshell thickness and yolk color. In conclusion, microbial phytase supplementation to the diets of older hens could improve production performance, extend the peak laying period, and alter the egg quality parameters.     

Effect of supplementary choline on the performance of broiler breeders fed on different energy sources

1. Laying performance, egg quality, fertility and hatchability, and fat deposition in liver and abdomen were recorded in broiler breeders (29 to 48 weeks of age) fed on diets containing perarl millet (Pennisetum typhoides) (PM), broken rice (BR) or yellow maize (YM) (600 g/kg diet). Constant ratios of metabolisable energy (ME) to other nutrients were maintained in all the diets. Food grade choline chloride (50%) was added to the diets at 3 concentrations (0, 760 and 1,520 mg/kg). Each diet was offered to 3 replicate groups of 15 birds (12 hens and 3 cockerels), maintained in deep litter pens, to provide 1.46 MJ ME/bird/d. 2. Neither the source of energy nor dietary choline content had any influence on hen-d egg production, fertility or hatchability. Food efficiency and egg weight were significantly reduced in BR-fed groups compared to those fed on the other energy sources. 3. The efficiency of energy and protein utilisation increased and liver fat content was decreased significantly by dietary choline supplementation. 4. Haugh unit score, egg shell weight, liver weight and intestinal weight were not influenced by either supplementary choline or the source of energy. However, the yolk colour index was significantly reduced in PM- or BR-fed groups compared to those fed on the maize-based diet. 5. Deposition of abdominal fat was significantly greater in BR-fed birds compared to those fed on the YM-based diet, while liver fat content was significantly greater in the birds fed on the PM-or BR-based diets than those based on YM. Although supplementation of the diet with choline had no influence on abdominal fat deposition, liver fat content was significantly reduced in birds given diet containing 760 mg supplemental choline/kg diet. 6. The present study indicates that PM or BR can be used as principal energy sources in place of YM in broiler breeder diets without affecting egg production, fertility or hatchability. Liver fat content can be reduced by adding choline at 760 mg/kg to diets based on different energy sources.     

Effect of feeding guanidinoacetic acid and L‐arginine on the fertility rate and sperm penetration in the perivitelline layer of aged broiler breeder hens

Two experiments were conducted to evaluate the effects of feeding guanidinoacetic acid (GAA) and L‐arginine (ARG) on fertility and sperm penetration (SP) rate of broiler breeder hens. In the first experiment, a total of 200 broiler breeder hens (Ross 308) aged 53 week were randomly allotted to four dietary treatments (0, 0.6, 1.2 and 1.8 g GAA/kg diet) with five replicates of 10 birds each. In the second experiment, 320 broiler breeder hens (Ross 308) were used from 53 to 62 weeks of age in a 2 × 4 factorial arrangement (0 or 1.2 g GAA/kg diet along with 0, 3, 6 or 9 g ARG/kg diet). The hens received a diet containing 2800 kcal ME/kg and 14% CP. Sixteen sexually mature Ross 308 breeder roosters (34 weeks old) were used to artificially inseminate the hens. Fertility of the hens was determined in 61 and 62 weeks of age. The sperm penetration holes in the inner perivitelline layer (IPL) overlying the germinal disc were enumerated on days 3 and 7 following each insemination. Adding GAA to the breeder diet increased the number of SPs in the IPL and fertility in both experiments (p < 0.01). The interactive effect of ARG and GAA on the SP and fertility was significant. Supplementary ARG increased the SP rate in the IPL (p < 0.01). In conclusion, dietary supplementation of GAA and ARG might be potentially used to improve the fertility of broiler breeder hens at the later phase of the egg production period.     

Internal Egg Temperature in Response to Preincubation Warming in Broiler Breeder and Turkey Eggs

Various methods of preincubation warming have been used in commercial hatcheries to increase hatchability, decrease incubation time, and increase embryonic blastoderm development. A study was conducted to determine the effect of preincubation warming and egg size on the warming rate of eggs. Three egg groupings were evaluated: small broiler breeder eggs (52 to 57 g), large broiler breeder eggs (64 to 69 g), and turkey eggs (74 to 107 g). The eggs were subjected to 2 temperature treatments. The conventionally incubated eggs were moved directly from storage (17.5°C) to the incubator (adjusted to 37.5°C). The preincubation warmed eggs were moved from the storage room to the preincubation room (28°C) for 12 h and then to the incubator. Internal egg temperature was measured once per minute to calculate the rate of warming. The warming rate potential (k value) differed for egg type and temperature treatment. The values for small and large broiler breeder eggs and turkey eggs were 0.0506, 0.0488, and 0.0471 kJ/min per kJ of energy in the egg, respectively. This study characterizes the maximum rate of temperature change that occurs when eggs are transferred from a storage or preincubation area to the incubator, creating baseline values for future work with the modification of hatchery management protocols. These data can contribute to more informed decisions regarding hatchery temperature profile strategies and their effect on the developing embryo.     

Effect of semen storage time and number of spermatozoa inseminated on the fertility and hatchability of eggs from dwarf broiler breeder hens

Semen from commercial breeder males was diluted two-fold and stored for 6 and 24 h at 2 to 3 degrees C. For each storage period, groups of caged dwarf broiler breeder hens from the same strain were inseminated with 300, 200 or 100 x 10(6) spermatozoa. Three replicates of 15 birds were inseminated per treatment. Control hens were inseminated with 150 x 10(6) fresh, undiluted spermatozoa. Inseminations were performed for 5 consecutive weeks during a first (32 to 36 weeks of age) and for 6 consecutive weeks during a second experimental period (42 to 47 weeks). During weeks 33 to 36 of the first period, only 24 h storage and 100 x 10(6) spermatozoa produced lower (P less than 0.05) hatchability of all eggs set than the control (84.4 compared to 88.6%). During weeks 43 to 47 of the second period, no significant differences between treatments were observed. Embryonic mortality, measured at different periods during incubation, was not affected by the storage time or the number of spermatozoa inseminated.     

植酸酶对种鸡生产性能及种蛋孵化性能影响的研究

种鸡在生产条件下，利用植酸酶水解饲料中植酸的原理，观察商品植酸酶替代磷酸氢钙对种鸡生产性能和种蛋孵化性能的影响和评价其实际可应用性。选用２８～３６周龄的肉用黄种鸡（ＮＫ２７１），在饲料中添加３００单位植酸酶替代磷酸氢钙（ＤＣＰ）提供的１．８ｇ无机磷。结果表明：植酸酶使种鸡的产蛋率（＋０．６６％）、日耗料量（－０．７１％）、破蛋率（－９．３％）、不合格种蛋（－４．９５％）、种蛋受精率（＋０．２９％）和１２天活胚率（＋０．７８％）均得到改善，但差异不显著（Ｐ＞０．０５）；而入孵种蛋健雏率（＋１．８９％）、１２天活胚蛋健雏率（＋１．６６％）和残次雏率（－１６．１１％）则优于对照组，差异极显著（Ｐ＜０．０１）。因此，可以认为不仅在种鸡饲料中可用商品植酸酶替代磷酸氢钙，而且对种鸡和种蛋的几乎全部重要生产和繁殖指标，都有不同程度的良好作用。根据目前市场上磷酸氢钙的品质（含氟量）状况，使用植酸酶能够大幅度减轻以至于杜绝由磷酸氢钙导致的氟中毒问题。同时能够预见，使用植酸酶可以大幅度降低排泄物中的含磷量，并能减少对自然环境的污染。可见，植酸酶在种鸡饲料中具有重要的实际应用价值。