Effects of breeder age and short-term temperature stimulation during incubation on performance, organ weight, and carcass yield in male and female broilers

Birds develop thermoregulatory control during the last days of incubation. Different temperature conditioning programs have been proposed to prepare broiler chicks for post-hatch life. This study aimed to investigate the effects of short-term temperature (STT) stimulation and breeder age on hatching performance, embryo development, yolk absorption, and post-hatch performance of male and female broilers. A 2 × 2 factorial completely randomized design was used, with two breeder ages (30 and 60 wk), two temperature incubation programs (control and STT), and 2,520 eggs per treatment. Eggs were distributed in two large-scale commercial incubators with a capacity of 120,960 eggs. The control group was subjected to a standard single-stage incubation program (37.2-37.4 °C), whereas the STT group was subjected to a temperature increment of 1 °C for 4 h on embryonic days 16, 17, 18, and 19. Embryos were analyzed at 16 and 19 days of incubation, and chicks at hatch. At 19 days of incubation, STT conditioning resulted in lower yolk sac weight in embryos from 60-wk-old breeders and higher relative weight of the gastrointestinal tract in embryos from 30-wk-old breeders. At hatch, males had lower residual yolk weight, females had greater length, and chicks from 60-wk-old breeders subjected to STT had higher body weight and relative weight of the gastrointestinal tract. Eggs from 30-wk-old breeders showed higher fertility and hatchability and lower infertility, mortality, and second-grade chick percentages. Regarding performance, it was found that males had higher body weight from 7 to 42 days of age and higher whole leg yields. Females, on the other hand, had higher fat yields. Breeder age and sex influenced gastrointestinal tract development, carcass yield, and performance. A 1 °C increase in incubation temperature for 4 h from days 16 to 19 of incubation affected yolk absorption and digestive tract development in chicks from 60-wk-old breeders without, however, influencing performance results.

Response in Growth, Scute Development, and Whole-Body Ion Composition of Acipenser fulvescens Reared in Water of Differing Chemistries

In fishes, environmental ion availability can have substantial effects on growth and development. This study examined the development of Lake Sturgeon in response to the varying environmental ion availability that they experience as part of a conservation stocking program. We reared sturgeon in natural water from the Coosa River, which had higher concentrations of Mg2+, Na+, and Zn2+ than standard hatchery conditions, while [Ca2+] at the Warm Springs National Fish Hatchery was 2× higher than in the Coosa River. Eggs were hatched in each water type and the larvae were sampled at time points before and after yolk absorption during the first 8 weeks of development. Total length and weight in WSNFH larvae were significantly higher than larvae in Coosa River water starting at 8 dph, indicating that growth was dependent on the different environmental ion levels. Concentrations of the ions of interest were also determined for whole-body acid digests of the exposed Lake Sturgeon. We found that Lake Sturgeon reared in Coosa River water had significantly higher magnesium and zinc than Lake Sturgeon reared in WSNFH water (p < 0.05), while calcium was significantly higher in WSNFH than Coosa River water. This difference shows that different environmental ion concentrations also impact the overall development of larval Lake Sturgeon.

Mathematical modeling of the interaction between yolk utilization and fish growth in zebrafish, Danio rerio

Optimal embryonic development plays a major role in the health of an individual beyond the developmental stage. Nutritional perturbation during development is associated with cardiovascular and metabolic disease later in life. With both nutritional uptake and overall growth being risk factors for eventual health, it is necessary to understand not only the behavior of the processes during development but also their interactions. In this study, we used differential equations, image analyses, curve fittings, parameter estimation and laboratory experiments to quantify the rate of yolk absorption and its effect on early development of a vertebrate model (Danio rerio). Findings from this study establish a nonlinear functional relationship between nutrient absorption and early fish growth. We found that the rate of change in fish length and yolk utilization is logistic, that is the yolk decays rapidly for a period of time before leveling out. An interesting finding from this study is that yolk utilization reaches its maximum at 84 hours post fertilization. We validated our mathematical models against experimental observations, making them powerful tools for replication and future simulations.

Growth, survivorship, and predator avoidance capability of larval shortnose sturgeon (Acipenser brevirostrum) in response to delayed feeding

Larval shortnose sturgeon, reared at 17°C, were subjected to delayed feeding treatments of 0, 5, 10, 15, 18, and 23 days post-yolk absorption to examine effects of food deprivation on growth, survival, swimming activity, and escape capabilities. Starvation affected growth and survival but despite degree of starvation, larvae were able to resume growth and experience high survivorship following feeding. Specific growth rate based on larval dry weight for the period directly following first feeding was highest for the day 15 and 18 delayed feeding treatments. There were no differences in survival between the 0 and 5 day treatments, however survival was reduced to 71.2%, 45.4%, and 28.8% for 10, 15, and 18 day delayed feeding treatments, respectively. Shortnose sturgeon had a point-of-no-return (PNR; 55.7% initiated feeding) at ~19 days (or 42 days post-fertilization) following the full absorption of yolk. Mean percent swimming activity and swimming speeds showed an interaction between delayed feeding treatment and larval age, such that no differences were detected at 1 and 6 days post-yolk absorption, while these swimming behaviors generally increased or spiked as feeding was delayed for 10, 15, and 18 days post-yolk absorption. At 23 days post-yolk absorption, only swimming speed increased for larvae that were denied food for 18 days. While there was an interaction between delayed feeding treatments and age for proportion of larvae exhibiting an escape response, generally, larvae from all feeding treatments exhibited a positive escape response. There were also interactions between delayed feeding treatments and age post-yolk absorption for mean and maximum escape speeds, such that less aggressive escape responses were typically detected the longer larvae were denied food. Our research suggests that larval shortnose sturgeon increase physical activity during periods of starvation to find a food patch while remaining vigilant but maybe not as capable to defend against a predatory attack as fed individuals.

Effects of different wavelength from Light Emitting Diodes (LEDs) on growth and development in zebrafish (Danio rerio) embryos and larvae

A light environment in aquatic habitat is one of the essential physical parameters affecting the growth and physiology of fish. To investigate the effects of light on the growth of zebrafish embryos and larvae (Danio rerio), fishes were reared under the illumination of Light Emitting Diodes (LEDs) of different wavelengths, including green, red, blue, and white. Morphometric, neuromast staining with 2-[4-(Dimethylamino)styryl]-1-ethylpyridinium iodide (DASPEI) and Polymerase Chain Reaction (PCR) analyses were used to examine the initial development of sensory capacity in this study. On days 5, 6, and 7, the green light produced the most favorable result. Blue light consistently impacted early parameters such as eye development, egg yolk absorption, and total length. These impacts were synchronous with the initiation of feeding. Exposure to specific wavelengths of light can induce the appearance of gene expression, opn1lw1 detected opsin and (mtnr1ba and aanat2) were active under all four experimental lighting conditions. This retinal gene appears to be sensitive to ambient wavelength, but apparently, genes in the melatonin pathway are not.

STUDY ON THE DEVELOPMENT AND GROWTH OF LARVES OF TIGER GROUPER Epinephelus fuscoguttatus (Forskal, 1775) AT DIFFERENT MEDIA TEMPERATURES

Water temperature has an influence on the development and growth of fish larvae. The appropriate water temperature can caused the development and growth of fish larvae optimum. This research aimed to study the effect of water temperature on the development and growth of brown marbled grouper larvae. This experimental design used a completely randomized design that had 3 treatments (26-28°C, 28-30°C, 30-32°C) equipped with 3 replications each. The parameters observed were the duration of yolk absorption, morphogenesis of larvae, and growth of body length. Data of larval morphogenesis development were analyzed descriptively, while the duration of yolk absorption and larval growth were analyzed of variance and post hoc test using the Least Significant Difference (LSD). The results showed that water temperature influenced morphogenesis development, the duration of yolk absorption, and the growth of larval significantly different. The result showed, larvae had morphological development and duration of yolk absorption faster in warmer incubation media.

Interactions between Egg Storage Duration and Breeder Age on Selected Egg Quality, Hatching Results, and Chicken Quality

Egg storage duration and breeder age are probably interacting to influence egg quality, hatchability, and hatchling quality. To evaluate this interaction, the impact of breeder age (31, 42, 66 weeks) and storage duration (2, 5, 12, 19 days) was investigated on broiler breeder eggs (Arbor Acres). Thick albumen diameter and pH increased, and yolk dry matter decreased between 2 and 19 days of storage. With the increase of breeder age from 31 to 66 weeks, albumen height, percentage and dry matter and shell percentage decreased and the egg weight and yolk percentage, dry matter and diameter increased. Prolonged egg storage increased the yolk pH in all breeder ages, but earlier and steeper in the oldest breeders. Prolonged egg storage resulted in a lower hatchability of set and fertile eggs due to a higher percentage of embryonic mortality. Early mortality increased earlier and steeper with prolonged egg storage in the oldest compared to younger breeders. Between 5 and 19 days of storage, yolk free body mass, liver and proventriculus + gizzard percentages decreased, as well as hatchling length and yolk efficiency (yolk absorption per initial yolk weight). The latter effects were most pronounced in the younger than in the older breeders. Therefore, eggs are preferably stored shorter than 7 d, but if long storage (≥12 days) cannot be avoided, we recommend to store eggs of older breeders when egg quality and hatchability are most important. In case hatchling quality is most important, it would be better to store eggs of younger breeders (31 weeks) for a prolonged period.

Embryonic and larval development of Labeobarbus megastoma and Labeobarbus platydorsus(pisces: cyprinidae) in lake tana (Ethiopia)

The information on the early ontogeny of the endemic Labeobarbus megastoma and Labeobarbus platydorsus fish species of Lake Tana are absent. In this paper we describe for the first time the full developmental sequence from egg to fingerling in controlled conditions. In addition, information on larval behavior, identification and developmental rates are provided. Embryonic development lasted 50:30h (26.3°C) and 61:38 (23.4°C) for the two species L. megastoma and L, platydorsus respectively and larval development to the morphology until the fry became very similar to the adult fish lasted 40 days (24.4°C). The mean total length of the newly hatched larvae of L. megastoma and L. platydorsus were 5.7±0.03 and 6.4±0.03mm respectively. The larvae hatched with closed mouth and anus, unpigmented eyes, large yolk and complete yolk absorption and exogenous feeding started on day 10 (8.9±0.07 and 10.5±0.12mm TL for L. megastoma and L. platydorsus respectively). The first posterior swim bladder aeration completed 5 days and 5 days and 6 h with 8.4±0.06 and 8.2±0.08mm TL for L. megastoma and L. platydorsus respectively and show full juvenile pigmentation and behaviour on the 41st day.