Hatching Characteristics Research Articles

Effects of mannan-oligosaccharides’ supplementation on hatching characteristics of four close-bred flocks of Japanese quail breeders

The present study was conducted to evaluate the effects of mannan-oligosaccharides’ (MOS) supplementation on hatching characteristics of four close-bred flocks (CBFs) of Japanese quail (Coturnix coturnix japonica) breeders. A total of 960 Japanese quail breeders, aged 12 weeks old, were randomly selected and divided into four groups (n = 240) with twelve replicates (n = 20) in a completely randomized design (15 ♂ : 5 ♀). The birds were a fed corn-based basal diet (group D) or basal diet supplemented with MOS at the levels of 0.25 % (group A), 0.5 % (group B) and 1.0 % (group C) for 15 weeks. The collected data were analyzed by two-way ANOVA techniques using Statistical Analysis System. The fertility and hatchability of 0.50 % MOS-supplemented group was significantly higher than other treatment groups. Similarly, fertility and hatchability percent of fertile eggs of Kaleem flock was significantly higher than other flocks, while dead in-shells were significantly lower in Sadat flock. Conclusively, MOS supplementation positively influences the fertility and hatchability of quail breeders. Keywords : Fertility, hatchability, Japanese quail breeders, mannan-oligosaccharides, poultry biotechnology

Effects of different storage time on hatching results and some egg quality characteristics of rock partridge (A. graeca) (management and production)

In this research, partridge eggs were stored during zero to 7, 8 to 14, 15 to 21, 22 to 28, 29 to 35 and 36 to 42 d, respectively. The effect of different egg storage periods on egg protein and moisture rates, mineral contents, and some egg quality and hatching characteristics were investigated. The extension of egg storage times didn't affect the external quality features like shell weight, shell thickness, and albumen rate, but it affected the yolk weight, yolk index, albumen index, and Haugh unit (P < 0.05). Yolk weight was increased and yolk index, albumen index, and Haugh unit values were decreased with the extension of storage time. Different storage times of partridge eggs did not have important effects on the protein rates. Protein and humidity rate of the eggs were 14.21 and 67.64%, respectively. There were some elements such as S, P, Na, K, and Ca, but Al, Cd, Co, Mo, and Pb could not be found in the partridge eggs. There is no effect of the storage time on the mineral content of the egg. Storage time had negative effect on fertility and hatchability after 21 d of storage d, but no effect on hatchability of fertile eggs. As this study showed, partridge eggs are resistant to long storage times, as partridge egg proteins can resist degradation in the optimum storage times. To determine egg degradation, the study should be focused on partridge eggshell features, which are responsible for degradation. As a result of this research, partridge eggs can be stored for 21 d under optimum storage conditions without any negative hatchability results.

Effect of egg weight and amount of protoporphyrin and biliverdin in the egg shell on hatching characteristics and embryonal mortality in pheasants (Phasianus Colchicus)

This study was performed to investigate the effects of egg weight and amount of protoporphyrin and biliverdin in the eggshell on hatchability and embryonic mortality in pheasants. A total of 1908 eggs obtained from 48 weeks old pheasants were used in the study. The eggs were divided into three colour groups (dark brown, light brown and green) and two weight groups (up to 32 g and above 32 g). For the weight groups, there were significant differences in the hatchability of fertile eggs (P<0.01) and late period embryonic mortality (LPEM) (P<0.05). The highest hatchability of fertile eggs and the lowest embryonic mortality were determined in light eggs (≤32 g). In terms of eggshell colour groups, there were significant differences in the hatchability of total eggs (P<0.01); hatchability of fertile eggs (P<0.01); and early (P<0.01), middle (MPEM) (P<0.05) and late period (P<0.05) embryonic mortality. In present study, the highest hatchability and the lowest embryonic mortality rate (except for MPEM) were in the dark brown eggshell group. For all groups, the differences in fertility rate were insignificant (P>0.05). The highest hatching characteristics and the lowest embryonic mortality rates were determined in the dark brown eggs. Based on these results, to achieve higher a hatchability of total eggs, hatchability of fertile eggs and a lower embryonic mortality rate, it may be beneficial selection of dark brown pheasant eggs

Inheritance and World Variation in Thermal Requirements for Egg Hatch in Lymantria dispar (Lepidoptera: Erebidae).

Mode of inheritance of hatch traits in Lymantria dispar L. was determined by crossing populations nearly fixed for the phenotypic extremes. The nondiapausing phenotype was inherited via a single recessive gene and the phenotype with reduced low temperature exposure requirements before hatch was inherited via a single dominant gene. There was no evidence for sex-linkage or cytoplasmic effects with either gene. Eggs from 43 geographic populations were evaluated for hatch characteristics after being held for 60 d at 5°C followed by incubation at 25°C. There was considerable variation both within and among the populations in the proportion able to hatch, time to first hatch, and average time to hatch. Egg masses with reduced requirement for low temperatures before the eggs were ready to hatch were present in all subspecies of L. dispar and the phenotype was not fixed in most populations. The populations clustered into three distinct groups, and climatic variables were found to be rough predictors of those groups. Variation in hatch phenotypes between populations is likely an adaptation to local climate and within a population provides a bet-hedging strategy to ensure that at least some hatch synchronizes with host leaf-out. Continued vigilance to prevent movement of populations both within and between countries is warranted, because some of the alleles that confer nondiapause or reduced low temperature requirements before egg hatch are not present in all populations and their introduction would increase variation in egg hatch within a population.

Tavuklarda Yumurta Şekil İndeksinin Kuluçka Özellikleri Üzerine Etkisi

In this study, the effects of egg shape index on hatching characteristics (fertility rate, embryo mortality, hatchability of fertile eggs and hatchability), egg weight loss, chick weight, sex ratio and quality of chicks were investigated. A total of 960 eggs of ATAK- S hybrid parents obtained from Ankara Poultry Research Station were divided into three different groups (SI≤71, 72≤SI≤76, SI≤77) based on shape index and were used. A significant relationship between fertility rate and late embryonic mortality was found in the shape index groups. On the other hand, no differences were found in the rate of weight loss at 18 day, early and middle embryonic mortality, malposition rate, hatchability, sex ratio and chick quality among the shape index groups. It was concluded that shape index affected the hatching results and also that eggs of abnormal shape index should not be used for hatching.

Interactive effects of incubation temperature and salinity on the early life stages of pacific cod Gadus macrocephalus

The combined effects of incubation temperature and salinity on the early life stages of Pacific cod Gadus macrocephalus were examined under controlled laboratory conditions. Data were collected from two synchronized experiments. Experiment 1 was designed to evaluate the interactive effects of incubation temperature and salinity on the hatchability of fertilized G. macrocephalus eggs. Experiment 2 was set up to evaluate the interactive effects of incubation temperature and salinity on the time from hatching to 50% mortality of the non-fed yolk-sac larvae (M50). The results show that temperature could significantly influence the development and hatchability of the larvae, as well as the hatching characteristics of G. macrocephalus. Viable hatch was significantly influenced by salinity when the upper and lower thermal limits were approached and shows the synergism of low salinity on egg development at low-temperatures and conversely inhibitory effects of low-salinity at high-temperatures. Data on developmental rates as influenced by temperature were presented at each tested salinity level. No influence of salinity was found at the temperature levels tested. Dome-shaped quadratic curves were fitted to the relationship between temperature and the incidence of larval size and yolk storage at hatch for most of the tested salinity levels. The effect of salinity across all temperatures, however, had a much smaller influence on larval size and no effect on yolk storage at hatch. The influence of temperature on larval duration (time from hatching to M50) could be described in all cases by an exponential power function. Evidence on the synergism of low salinity at low-temperatures and conversely inhibitory effects of low-salinity at high-temperatures was also observed. The results were discussed in reference to salinity modified temperature effects on the early life stages of G. macrocephalus. Maximum hatchability and larval size at hatch, and moderate salinity tolerance and larval duration suggest an optimal temperature range of 4°C to 6°C for the survival and development of the early life stages of G. macrocephalus in the field.

Effects of dietary organic or inorganic manganese, zinc, copper and chrome supplementation on the performance, egg quality and hatching characteristics of laying breeder hens

Bu arastirma, iki farkli seviyede organik veya inorganik Mn, Zn, Cu ve Cr karisiminin (sirasiyla, 80, 60, 5 ve 0.15 mg/kg ve 40, 30, 2.5 ve 0.07 mg/kg) damizlik yumurta tavuklarinin performans, yumurta kalitesi ve kulucka ozelliklerine etkilerini karsilastirmak amaciyla duzenlenmistir. Arastirma, 50 haftalik yasta, toplam 360 adet Barred Rock hatti ile baslatilmis ve 16 hafta surdurulmustur. 4 ana grup her biri 15 tavuk iceren 6 tekerrure rastgele dagitilmistir. Farkli iz mineral uygulamalari yasama gucu, canli agirlik kazanci, yumurta verimi, yumurta agirligi ve kutlesi, yem tuketimi ve yemden yararlanma gibi performans parametreleri uzerinde onemli bir etki gostermemistir. Yumurta kalite parametrelerinden, hasarli yumurta orani, sekil indeksi, kabuk orani ve kalinligi, ak yuksekligi ve haugh birimi bakimindan gruplar arasinda onemli farkliliklar bulunmamistir. Bununla birlikte, dusuk iz mineral seviyesi kabuk kirilma mukavemetinde onemli bir azalmaya sebep olmustur. (P < 0.05). Farkli iz mineral uygulamalari, kuluckalik ve dollu yumurta oranlari uzerine onemli bir etki gostermemistir. Organik (metiyonin selati) Mn, Zn, Cu ve Cr’ un yuksek (sirasiyla, 80, 60, 5 ve 0.15 mg/kg) duzeyleri cikis gucu ve kulucka randimanini diger gruplara gore artirmistir (P < 0.05)

Interactive effects of temperature and salinity on population dynamics of the calanoid copepod Acartia tonsa

The euryhaline, eurytherm copepod Acartia tonsa plays a key role in many marine food webs as a grazer on phytoplankton and as prey species for commercially important planktivorous fishes. The different populations of this cosmopolitan species experience a wide range of environmental conditions. This study aims to elucidate the response of A. tonsa to changes in multiple environmental factors. The effects of temperature (T), salinity (S) and the interaction of both variables on recruitment processes were investigated to show potential influences of changes in environmental conditions on its life cycle and population dynamics. Estuarine conditions appeared to be optimal for reproduction, despite the marine origin of the population. Interactive effects of T × S were more pronounced when the population was exposed for a longer period of time to constant laboratory conditions. Potential resting eggs were identified based on morphology and hatching characteristics, and were mainly produced at high S and low T. Our results emphasize the importance of investigating the combined effects of different physical factors to gain a better understanding of potential changes in population dynamics resulting from climate-induced changes in key environmental factors.

Effect of egg weight on hatching characteristics of emu eggs

The study was carried out to investigate the effects of egg weight on hatchability traits in emu (Dromiceius novaehollandiae) eggs. Emu eggs (393) that hatched from 3 different egg weight groups (below 500 g (G 1), 501 to 600 g (G 2) and above 601 g (G 3)) were used in the experiment. Hatching traits such as percentage of infertile eggs, early embryonic mortality, late embryonic mortality, dead-in-shell, chicks hatched out, total egg hatchability, fertile egg hatchability, fertility and chick livability were investigated. The mean±SE percentage of early embryonic mortality, late embryonic mortality, dead-in-shell, chicks hatched out, total egg hatchability, fertile egg hatchability, fertility and chick livability were statistically significant for different egg weight groups. The better hatching traits and livability of chicks were obtained from the medium emu eggs weighed between 501 and 600 g then the heavy (above 601 g) and small (below 500 g) egg weight groups.

Combined effect of temperature and salinity on hatching characteristics of three fairy shrimp species (Crustacea: Anostraca)

The combined effects of temperature and salinity on hatching performance of three anostracan species, Phallocryptus spinosa, Branchinecta orientalis and Streptocephalus torvicornis from East and West Azerbaijan, Iran, were studied. The cysts were kept for 10 days at seven different temperatures (12, 15, 18, 21, 24, 27 and 30°C) and four salinity conditions (0, 5, 10, and 15 gL ‐1 ), and the effects of the resulting 28 experimental conditions on hatching patterns (duration of pre-hatching period, hatching percentage at first day of hatching, cumulative hatching success) were examined. Results were tested by ANOVA and multiple regression was applied to generate contour models by polynomial equation. The hatching performance in all species was significantly affected by temperature and salinity. Based on contour plot analysis, maximum hatching for P. spinosa, B. orientalis and S. torvicornis cysts was registered at temperatures 19-25oC, 18-23oC and 16-20oC, respectively, within the same salinity range of 0-1 gL ‐1 . The highest cumulative hatching success among the species was observed in P. spinosa at the combination of 24°C and 0gL ‐1 (88. 98%). No hatching was observed for eggs of S. torvicornis and B. orientalis incubated at lower ( 27oC) temperature, respectively. The pre-hatching period was prolonged with increase in salinity and decrease in temperature and was highest in P. spinosa (7.7 days at 12°C and 15 gL ‐1 salinity). High hatching success was observed over wide ranges of temperature and salinity in P. spinosa eggs which demonstrates one of the possible mechanisms responsible for the wide distribution of this species.

Study on the Hatching Characteristics and Diet of the Stick Insect, Baculum elongatum (Phasmida: Phasmatidae) for Artificial Mass Rearing

Baculum elongatum has several peculiarities such as parthenogenesis, unique external features, changing body color, and dropping oviposition, which makes it a potential economically useful insect. Oviposition was performed by females without fertilization by the sperm of males. The oviposition period was <TEX>$42.2{\pm}22.7$</TEX> days and the number of eggs per female was <TEX>$109.5{\pm}70.5$</TEX> eggs. The hatch rate was 73.3% at <TEX>$25^{\circ}C$</TEX> and 66.7% after low temperature treatment (<TEX>$8^{\circ}C$</TEX> for 60 days). In nature, B. elongatum overwinters as an egg, but it can be assumed from the results that cold temperatures were not required for hatching. The hatch rate was 98.2% in the treatment using floral foam, fermented sawdust, and leaves. The developmental period was <TEX>$100.9{\pm}4.2$</TEX> days for eggs, <TEX>$55.3{\pm}4.6$</TEX> days for nymphs, and <TEX>$49.7{\pm}16.0$</TEX> days for adults. The length of the eggs was <TEX>$0.33{\pm}0.0$</TEX> cm and the lengths of the nymphs were clearly distinguishable according to the instar stage. Clover(Trifolium repens) was an excellent diet as it was similar to the host plant and could be used as an alternative diet. The rate of reaching adulthood for the insects was 66.7% on an artificial diet containing 25% acacia leaves. For sustainable mass rearing of nymphs or adults of B. elongatum, a natural diet could be used such as acacia (Robinia pseudoacacia), white oak (Quercus aliena), chestnut (Castanea crenata var. dulcis), and bush clover (Lespedeza bicolor), or an alternative diet such as clover or artificial diet.

Comparative hatching characteristics of nonparasitic and parasitic icterids: is the hatching of cowbird young constrained by an unusually thick eggshell?

Studies of avian brood parasitism have provided some of the best evidence of coevolutionary arms races. One of the parasitic adaptations exhibited by cuckoos (family Cuculidae) and cowbirds (family Icteridae) is the development of a thick eggshell, presumably to avoid damage from puncture ejection by some hosts and/or accidental damage during egg-laying in the host nest. However, it is unknown whether this trait constrains the hatching of parasitic young. The differences in hatching characteristics between the host red-winged blackbird (“redwing;” Agelaius phoeniceus) and the parasitic brown-headed cowbird (Molothrus ater) were examined. Prehatched cowbird young were found to spend more time hatching than pre-hatched redwing young and to emit click sounds at a greater rate in relation to pulmonary respiration than pre-hatched redwing young. However, cowbird hatchlings appear to have evolved other hatching-related traits that may compensate for the greater hatching effort, such as body parts and an egg tooth that are relatively large compared with those of redwing hatchlings.

Avian cholera, post‐hatching survival and selection on hatch characteristics in a long‐lived bird, the common eider Somateria mollisima

Infectious diseases can have dramatic impacts on animal population dynamics, but how they influence vital rates remains understudied. We took advantage of the appearance of an avian cholera epizootic in an arctic colony of common eiders Somateria mollissima to study variation in juvenile survival and selection on hatch characteristics in relation to this highly infectious disease. Avian cholera is one of the most important infectious diseases affecting wild birds and is thought to primarily affect adult survival. Here, we show that avian cholera was associated with a 90% decline in duckling survival, leading to almost zero recruitment. Before the cholera outbreak, there was significant stabilizing selection on hatching date and significant positive directional selection on hatching mass. During cholera outbreaks, selection on hatch characteristics was no longer significant. These results were based on a low sample of surviving ducklings in cholera years, but suggested that date and mass at hatching did no longer affect duckling survival in the presence of cholera. These effects of avian cholera on post‐hatching survival were likely not only the consequence of the disease per se, but also a consequence of an increase in predation rates that followed the emergence of avian cholera. Our results emphasize the dramatic direct and indirect impacts that infectious disease can have on vital rates, and thus population dynamics.

Wolbachiamodulates Chikungunya replication inAedes albopictus

The Aedes albopictus mosquito has been involved as the principal vector of recent major outbreaks due to the chikungunya virus (CHIKV). The species is naturally infected by two strains of Wolbachia (wAlbA and wAlbB). Wolbachia infections are thought to have spread by manipulating the reproduction of their hosts; cytoplasmic incompatibility is the mechanism used by Wolbachia to invade natural populations of many insects including Ae. albopictus. Here, we report a study on the effects of removing Wolbachia from Ae. albopictus on CHIKV replication and examine the consequences of CHIKV infection on some life-history traits (survival and reproduction) of Wolbachia-free Ae. albopictus. We found that Wolbachia-free mosquitoes maintained a highly heterogeneous CHIKV replication compared to Wolbachia-infected individuals. In Wolbachia-infected Ae. albopictus, the regular increase of CHIKV followed by a steady viral load from day 4 post-infection onwards was concomitant with a decline in Wolbachia density. This profile was also detected when examining the two key organs for viral transmission, the midgut and the salivary glands. Moreover, Wolbachia-free Ae. albopictus was not altered in life-history traits such as survival, oviposition and hatching characteristics whether infected or not with CHIKV. We found that Wolbachia is not essential for viral replication, its presence could lead to optimize replication from day 4 post-infection onwards, coinciding with a decrease in Wolbachia density. Wolbachia may regulate viral replication in Ae. albopictus, with consequences on survival and reproduction.

Interactions between field populations of the potato cyst nematode Globodera pallida and Rhizoctonia solani diseases of potatoes under controlled environment and glasshouse conditions

Abstract This research elucidates interactions between Globodera pallida and Rhizoctonia solani (AG3) by comparing disease development in potato plants inoculated with G. pallida and R. solani. The effects of juvenile population density and time of infestation on R. solani disease were investigated in controlled environments. Plants were inoculated with a range of densities of second-stage juveniles (J2) of G. pallida (800, 4000, 10 000, 20 000 and 40 000 J2/plant) and R. solani at 2, 4 and 6 weeks after planting and a single treatment of G. pallida density and R. solani alone. The experiment demonstrated that greatest disease incidence and severity occurred when high population densities of G. pallida were applied at an early stage of plant development. To determine if this effect could explain differences in R. solani disease incidence and severity following interactions with individual field populations of G. pallida, a glasshouse experiment was conducted using two populations of G. pallida with known hatching characteristics (fast and slow hatching). The experiment revealed that a combination of a fast-hatching population with R. solani caused significantly more R. solani disease incidence and severity than a population of G. pallida with slower hatching characteristics.

Effect of location of eggs in the incubator on hatchability of eggs from Bronze turkey breeders of different ages

The objective of this study was to determine the effect of location in an incubator on the hatching characteristics of eggs obtained from Bronze turkeys of different ages, viz. at the ages of 8, 10 and 12 months. In the study 330 eggs were placed in each of six locations within an incubator, totalling 1 980 eggs from each age group, and 5 940 eggs overall. The highest fertility rate and hatchability of all eggs set, and of fertile eggs were recorded in the eggs from 10-month old breeders. The lowest rates of shell adhesion deaths, null poults and poults with abnormalities were also observed in this group. In all age groups investigated, the hatchability of all eggs set and of fertile eggs was the highest in eggs placed in the front of the machine. Furthermore, early and middle stage deaths during incubation were lower in the front of the incubator compared to the back. The differences between eggs placed in the upper, middle and lower parts of the machine with respect to the investigated characteristics were not statistically significant. Although these results were obtained from a specific incubator, the locations inside and all applications (temperature, humidity, shaking, etc.) were within accepted standards. Therefore, results are applicable, in general.

Effect of an herbal essential oil mixture on growth, laying traits, and egg hatching characteristics of broiler breeders

The effects of supplementing a basal diet with 2 levels of an essential oil mixture and an antibiotic on the growth, laying traits, and egg hatching characteristics of broiler breeders were examined in this study. Nine hundred sixty female and 128 male breeders at an age of 1 d old were randomly allocated to 16 replicates (i.e., 4 replicates of 4 dietary treatments) in a floor pen trial. Two levels of an essential oil mixture (EOM; i.e., 24 and 48 mg of EOM/kg of diet) and an antibiotic (i.e., l0 mg of avilamycin/kg of diet) were added to the basal starter, grower, and laying diets from 0 to 45 wk of age. Daily feed allocations were adjusted to produce a target BW and egg production rate of the breeders throughout the experimental period. The BW of the males and females were determined at 12, 21, and 45 wk of age. Livability during the growing and laying period was not affected by the dietary treatments. The fertility and hatchability of total eggs set were positively affected by the supplementation of the EOM in the diet (P < 0.01). The hen-day egg production, hatching egg weight, settable egg ratio, hatching of fertile eggs, extra large egg rate, and proportion of chick weight to egg weight were not affected significantly. The higher level of EOM (48 mg/kg) added to the diet led to the hatching of the heaviest chickens; the lower level of EOM (24 mg/kg) and antibiotic treatments led to the hatching of the intermediate weight chickens, followed by the control treatment (P < 0.01). Hens given the lower level of EOM in their diets produced a higher number of settable eggs and chicks as compared with those of other treatments, whereas hens fed the control diet yielded the lowest total settable eggs and chicks throughout the experimental laying period (P < 0.05). The results of this study showed that supplementing diets with EOM improved fertility, the hatchability of total eggs set, total settable eggs, total chicks, and the chick weight of broiler breeders.

Stability of Heterodera glycines (Tylenchida: Heteroderidae) juvenile hatching from eggs obtained from different sources of soybean, Glycine max

AbstractThe hatching behaviours of Heterodera glycines second-stage juveniles (J2) from eggs obtained from laboratory and glasshouse cultures, and from the field, were examined in vitro using large scale (Baermann funnel) and small-scale (depression slide) assay designs. Hatching of J2 from cultured eggs was robust, whereas J2 from field eggs hatched very poorly in vitro (&lt;1% total cumulative percentage hatch). Qualitative aspects of hatch were stable as hatching of J2 from eggs from all sources was linear from 2 through to 8-10 days. By contrast, quantitative aspects were more variable. Total cumulative percentage hatch typically ranged from 45 to 70% but approached 90% depending upon the source of the cultured eggs. Egg density (eggs/cm2) affected hatch of J2 in the large scale in vitro system, with total cumulative percentage hatch significantly greater at 3100 eggs/cm2 than at 420 eggs/cm2. The poor hatch of J2 from field eggs was lost after two generations in culture and replaced by the typical hatch characteristics of J2 from eggs from an established culture. This included both qualitative and quantitative elements. Stability of H. glycines hatching behaviour and its reflection of dormancy and diapause of J2 are discussed.

Short Communication Effects of short chain fatty acid (SCFA) supplementation on performance and egg characteristics of old breeder hens

A study was conducted to determine the effect of supplementing the diet of breeder hens with a short-chain fatty acid (SCFA) premix, containing 509 g fatty acid salts/kg of which 285 g were calcium butyrate, on their eggshell characteristics and the hatching percentage of the eggs. One thousand six hundred 66-week old White Bovans laying breeder hens were used in this experiment. They were housed in eight identical pens, each containing 200 birds, and four pens were used per treatment. The SCFA premix was included at 1000 mg/kg in the treatment diet, and fed for a period of nine weeks. Responses were compared with an unsupplemented treatment. Supplementation started when the hens were 66 weeks old. From day 75 eggs were collected for the next seven weeks and the occurrence of cracked, dirty and misshapen eggs was recorded, and the hatching percentage of the eggs was determined. Eggshell strength was lower in eggs from the control (1.76 ± 0.05) than from the treatment group (2.07 ± 0.03). The percentage of eggs produced by the control group (68.6 ± 0.08) was significantly lower than that by the supplemented group (71.5 ± 0.15). Percentage of dirty, cracked and misshapen eggs, and the hatchability percentage of the control group (1.15 ± 0.03, 3.44 ± 0.05, 6.27 ± 0.03 and 88.93 ± 0.06, respectively) were also significantly lower than in the group receiving SCFA (0.47 ± 0.03, 2.21 ± 0.03, 3.81 ± 0.03 and 93.36 ± 0.05, respectively). It was concluded that dietary supplementation of SCFA to layer breeder hens from 66 weeks of age onwards improved eggshell strength, reduced the percentage of dirty, cracked and misshapen eggs and increased the hatching percentage of the eggs. The positive responses were suggested to be largely due to the butyrate in the SCFA. Keywords : Butyrate; SCFA; eggshell quality; hatching characteristics South African Journal of Animal Science Vol. 37 (3) 2007: pp.158-163

Developmental and Reproductive Effects of Low Cadmium Concentration on Artemia parthenogenetica

Hatching, reproductive, and lifespan characteristics of an Artemia parthenogenetica population from La Mata (Alicante, Spain) exposed to cadmium were studied. No effects on percentage of cyst hatched nor time of hatching were observed on cysts exposed from 0.01 to 5 mg Cd/L. Cohorts of Artemia were chronically exposed to cadmium in life-table experiments to test whether ecologically relevant impacts may occur after several generations of exposure to a very low concentration of cadmium. Chronic toxicity tests were performed using neonates of a third generation of shrimps exposed to 0.08 mg Cd/L (1/1000 of the LOEC for 24 h acute toxicity test). No significant reduction in the intrinsic rate of natural increase (r m ) was found as a result of cadmium exposure, although the age-specific fecundities of the cadmium exposed shrimps were lower than those of the controls. A significant decrease in the prereproductive period and a reduction in the percentage of fertile females was also found as a consequence of the metal exposure.