The effect of dietary iodine on the hatchability of eggs from two commercial strains of turkeys

Effect of dietary canthaxanthin and iodine on the production performance and egg quality of laying hens

In this study, we aimed to evaluate the effect of canthaxanthin (CX) and iodine (I) on the production of laying hens, on counteracting debilitation of the vitelline membrane, and on inhibiting Salmonella growth in eggs stored at 30°C. Three hundred hens were reared in cages. Birds were divided into six feeding groups (10 hens × 5 repetitions) that were administered 0, 3 or 6 ppm of CX and 1 or 10 ppm of I with their diets. Laying rate, egg weights, and feed conversion ratios were controlled. The quality of fresh eggs was assessed in wks 25-26, 48-50 and 62-63 of hens lives. An additional batch of eggs was incubated at the temperature of 30°C, and egg quality changes were monitored on days 3, 6 and 9 of storage. Additionally, eggs collected from four experimental groups of hens whose diets had been iodated with 1 or 10 ppm of I and supplemented with 0 or 6 ppm of CX were infected under laboratory conditions with Salmonella, and incubated for 5 and 10 d. The laying rate, egg weights, and feed conversion ratio were significantly improved. Dietary inclusion of CX contributed to a higher resistance of the vitelline membrane of egg yolks, but only for fresh eggs. Vitelline membrane degradation during egg storage at 30°C was significantly counteracted by dietary inclusion of I at a dose of 10 ppm. The same I dose resulted in the complete inhibition of Salmonella growth until day 10 of incubation, but exclusively for eggs collected from 40-week-old hens. Dietary supplementation with 10 ppm of I was found to impart high level of resistance to the vitelline membrane against the growth of Salmonella in case of eggs stored at 30°C; therefore, I was found to be more beneficial by ensuring longer preservation than that of CX. However, dietary supplementation with CX was found to increase the resistance of vitelline membrane in fresh eggs.

Modulation of post-hatch growth and immunity through in ovo supplemented nutrients in broiler chickens

BACKGROUND

Early post-hatch growth and immunity were assessed through in ovo supplementation of nutrients: amino acids (AA), trace elements (TE), fatty acids and vitamins (FAV) grouped under humoral immunity (HI) or cell-mediated immunity (CMI) on the 18th day of incubation at the broad end of the egg using a 25 mm needle.

RESULTS

Hatchability in AA groups was better than TE and FAV groups. CMI groups had better hatchability than HI groups. AA and TE groups had higher chick-to-egg weight ratio (P < 0.01) than the FAV group. At 3 weeks of age, a higher body weight (P < 0.01) was recorded in AA for CMI, TE for HI and FAV for HI groups. FAV-injected chicks had a higher bursa weight at hatch, but TE chicks had higher thymus weight at the 3rd week of age. Humoral immune response was not different in in ovo injected chicks compared to control. CMI was higher (P < 0.01) in AA for CMI, TE for CMI and FAV for CMI or HI nutrient-injected chicks.

CONCLUSIONS

In ovo injection of AA for CMI and TE for HI may accelerate growth of broiler chickens. In ovo injection of AA, TE or FAV may modulate CMI in chicks.

Effect of oxygen supplementation in the hatcher at high altitude on the incubation results of broiler eggs laid at low altitude

1. The object of this research was to investigate the effects of high altitude with supplementary oxygen during the last stage of incubation of broiler eggs laid at low altitude and incubated at low and high altitude. We analysed thyroid hormones and haematological variables. 2. The treatment groups were: low altitude (LA), high altitude with oxygen supplementation in the hatcher (HA-OX) and high altitude non-oxygen-supplemented (HA-NOX). 3. High altitude affected relative egg weight loss and early embryonic mortality. The hatchability of fertile eggs was lower at high than at low altitude. 4. Oxygen supplementation into the hatcher cabinet during the last stage of incubation decreased late embryonic mortality ratio (LEM(1)) and improved survival rates of embryos incubated at high altitude. 5. Eggs incubated at low altitude had a higher hatched chick weight and relative chick weight than those incubated at high altitude. Hatched chick weight and relative chick weight did not change with oxygen supplementation at high altitude. 6. High altitude caused an increase in plasma T(3) and T(4) concentrations as well as in the ratio of T(3):T(4) in embryos. High altitude newly hatched chicks showed a higher T(3):T(4) ratio than low altitude chicks; this ratio decreased with oxygen supplementation at high altitude. Altitude and oxygen supplementation did not affect the mean plasma T(4). 7. Newly-hatched chicks incubated at high altitude showed a higher plasma haematocrit (PCV) than the newly-hatched chicks from eggs incubated at low altitude. High altitude without supplementation increased haemoglobin (Hb), while oxygen supplementation returned the value to low altitude values.

Effects of supplementary iodine on the performance and egg traits of laying hens

1. This experiment was carried out to determine the effects of dietary iodine supplementation on the performance and egg traits of laying hens. A total of 600 SHSY type brown layers aged 21 weeks of age were chosen at random from a large flock. They were randomly distributed into 30 pens at 20 hens per pen. Each treatment comprised 6 replicates of 20 layers in groups of 5 birds. The diets were supplemented with 0, 3, 6, 12 and 24 mg/kg iodine as calcium iodate. The experimental period lasted 30 weeks. 2. There were no significant differences among the groups in body weight, food consumption, egg production, food consumption per kg eggs, eggshell index, eggshell breaking strength, shell thickness or egg yolk index. 3. Supplementation of the diet with 12 mg/kg iodine increased food consumption per dozen eggs compared to the groups fed on diets supplemented with 0 and 6 mg/kg iodine. 4. Egg weight was less in groups fed on diets supplemented with 12 and 24 mg/kg iodine than in the group receiving no iodine supplementation. 5. Iodine supplementation to provide 12 and 24 mg/kg reduced egg albumen index and egg Haugh units. 6. There were no significant differences among the groups in egg cholesterol and egg yolk cholesterol contents. 7. The iodine concentrations in egg yolk, egg albumen and whole egg increased with increased iodine supplementation. 8. As a result, the 3 and 6 mg/kg iodine supplementation of diet could be used to enrich the eggs with iodine without any adverse effect on performance and egg traits.

Environmental incubation factors influence embryonic thyroid hormones

Thyroid hormone responses in embryonic avian species are of two types, developmental and metabolic. Many studies have characterized the developmental function of the turkey embryonic thyroid, but few have characterized the metabolic function. Therefore, the purpose of this study was to describe the response of turkey embryonic thyroid hormones to three environmental factors. We proposed that embryonic thyroids from different genetic backgrounds would respond differently to changes in maternal diet and incubation temperature. Lines of turkeys known to have different embryonic growth and survival were examined in the current study. These eggs differ in egg weight, eggshell conductance, hatchling weight and organ maturity at the time of hatching. Eggs were produced throughout a 20 wk laying period and embryos were sampled at monthly intervals. Half of the hens producing the eggs were fed additional iodide in their diets, then, subsequently, half of each dietary treatment and line combination were incubated at either 36.8 C or 37.5 C to prolong the incubation period. Embryos were sampled during the final week of incubation when thyroid hormones become elevated to effect maturation and survival functions in turkey embryos. Embryonic thyroxine (T4) and triiodothyronine (T3) levels were assayed by RIA and compared among the treatments. Line, diet, and incubation period interacted to affect the levels of T4, T3 and T3 to T4 ratios in the turkey embryonic during late incubation. It was concluded that environmental factors can affect circulating thyroid hormone levels in turkey embryos, thus affecting metabolic functions, and the possibility exists to manipulate these circulating levels using environmental incubation conditions to improve hatchability.

Injection of Thyrotrophin-Releasing Hormone in Turkey Embryos Elevates Plasma Thyroxine Concentrations

The effectiveness of thyrotrophin-releasing-hormone (TRH) as a secretagogue in turkey embryos was tested. Fertilized turkey eggs were injected with TRH after 24 d of incubation. In an experiment to determine an effective route and dose for TRH administration, it was shown that a single manual injection of 200 microL containing 2.15 microg of TRH, into the air cell or the same injection containing 5.0 microg through the bottom of the egg, was effective in elevating plasma concentrations of thyroxine (T4) 60 min after injection. In a second experiment, 5 microg of TRH in a volume of 200 microL was injected through the bottom of each egg. Injections were performed mechanically into eggs held in a commercial incubator. The injection increased blood plasma T4 for 5 h after a 30-min lag. Eggs from two genetic strains of turkeys were injected in Experiment 3. The TRH elicited a persistent response for 120 min from one strain but resulted in a slightly depressed response from the other, suggesting that subtle differences in the maturation of the hypothalamo-hypophyseal-thyroid axis may exist in commercial strains of turkeys. We concluded that TRH is an effective secretagogue for T4 in 24-d-old turkey embryos.

Effects of maternal nutrition on hatchability

The effects of dietary factors on the development and viability of avian embryos have been extensively documented. A good nutritional status of the parent birds is crucial to the transfer to the egg of an adequate, balanced supply of nutrients required for normal development of the embryo. The consequences to the embryo may be lethal if the egg contains either inadequate, excessive, or imbalanced levels of nutrients. As nutritional deficiencies or excesses occur, it is common for the effects on the embryo to also become more severe and to occur at earlier stages of development. The type of nutritional stress signs visible in the embryo often depend upon the severity of the maternal nutritional stress. Diseases, parasitic infections, toxins, poisons, or drugs may also cause nutritional or pseudonutritional problems with hatchability.

Turkey breeder hen performance by strain during consecutive lay periods

The results of this study provide information about reproductive performance among commercially available strains of Large White Turkey breeder hens, Nicholas (N), British United (B), and Hybrid (H). The hens were managed identically through two consecutive lay periods, summer-fall (1st-yr) followed by winter-spring (recycled). Effects of the intensity (351 vs 24 lx) of supplemental light were evaluated during the 1st-yr lay period. Data were collected for onset of oviposition, egg production, BW, feed consumption, livability, egg weight, and egg components. Light intensity had similar effects on all variables measured. There were neither strain differences nor genetic interactions with light intensity treatment. There was no difference in livability among strains (P = .20) or between year of lay (P = .08), and there was no strain by year interaction. Body weight differed by strains and year and there was a significant strain by year interaction. In general, N were heavier than H or B in the 1st-yr and early recycle lay period, whereas H and B were similar in BW in both lay periods. Recycled hens of all strains were heavier than 1st-yr hens. The onset of lay was earlier in H than B or N in both lay periods and all three strains had a delay in onset of lay after recycling. Through 23 wk photostimulation the B hens produced more eggs per hen than N or H hens (B > N > H) and recycled hens produced more eggs per hen than 1st-yr hens. Strain, year, and strain by year interaction effects were significant for egg weight. The first eggs laid, as well as subsequent eggs in both lay periods, were heaviest in N hens. In all strains, percentage yolk increased and albumen decreased with time in lay. However, N hens had a smaller percentage yolk and greater albumen than H or B hens. The mean percentage shell was greatest in H hens.

Egg characteristics, carbohydrate metabolism, and thyroid hormones in late chick embryos from different genetic lines

Functional eggshell qualities, thyroid hormones, and carbohydrate metabolism of chick embryos at the end of incubation were compared between a modern (Arbor Acres line) and a randombred control population (Athens-Canadian Randombred). Embryos from the Arbor Acres genetic line developed in larger eggs with more albumen and less yolk than Athens Canadian Randombred lines. Percentage shell and functional eggshell properties measured as eggshell conductance constants did not differ between genetic lines. On a relative basis, hearts were generally smaller and livers heavier in Arbor Acres than in Athens-Canadian Randombred birds. Heart and liver glycogen concentrations were greater in Athens-Canadian Randombred than in Arbor Acres embryos. However, blood glucose was greater in Randombred than in Arbor Acres embryos only at internal pipping, a time of hypoxia and hypercapnia. Blood plasma concentrations of thyroxine did not differ significantly between the modern and Randombred embryos at any stage examined. Modern broiler chick embryos possessed greater concentrations of triiodothyronine as well as greater triiodothyronine to thyroxine ratios than Randombred embryos at external pipping and hatching. It can be inferred from the data that chick embryos differ in their use of carbohydrate during late development between modern and Randombred genetic lines.