Effects of sample handling,processing, storage,and hemolysis on measurements of key energy metabolites in ovine blood

Four experiments were conducted using mature Suffolk ewes to evaluate the effects of blood sample handling, processing and storage on measurements of the energy metabolites, β-hydroxybutyrate, total cholesterol, glucose, l-lactate, nonesterified fatty acid (NEFA), and triacylglycerol. In experiment 1 the effects of anticoagulants on metabolite measurements and packed-cell volume (PCV) were evaluated. Blood samples (n=12) were collected into one of four evacuated blood-collecting tubes: no anticoagulant (SER; yields serum), and plasma-yielding sodium heparin (HEP), sodium fluoride and potassium oxalate (NAF), and tripotassium ethylenediaminetetraacetic acid (K₃EDTA). Anticoagulant affected (P<0.05) metabolite values, with total cholesterol, triacylglycerol, and l-lactate highest in SER, and glucose highest in HEP; NEFA and β-hydroxybutyrate measurements were not affected (P>0.10) by anticoagulant. In addition, among the plasma-yielding tubes, PCV was highest in HEP and lowest in NAF (P<0.01). Experiment 2 investigated the effects of repetitive freezing-thawing cycles of plasma on metabolite levels. Blood samples (n=20) were collected using NAF tubes, and plasma was stored at −20 °C and thawed in a water bath (21 °C) 0, 1, 2, and 3 times within 18 h after collection. Compared with fresh samples (Thaw 0), by thaw 2, l-lactate increased (P<0.01) 5%, and glucose and total cholesterol decreased (P<0.001) 13 and 4%, respectively. Plasma NEFA increased 10% (P<0.01) between thaws 0 and 1, but returned to fresh levels (Thaw 0) with subsequent freeze-thaw cycles (P<0.05). Plasma β-hydroxybutyrate decreased (P<0.01) between thaws 0 and 1, but there was no further decline with subsequent freeze-thaw cycles (P<0.05). Experiment 3 evaluated the effects of plasma storage temperature (−20 °C versus −80 °C) and length (0–180 days) on metabolite levels in blood samples (n=12) collected in NAF tubes. All plasma metabolites were affected by storage length (day effect, P<0.01) but only total cholesterol values were affected by storage temperature, with values being higher in plasma stored at −20 than −80 °C (P<0.01). Glucose measurements were higher in samples stored at −20 °C for up to 30 days, but were higher thereafter in samples stored at −80 °C (storage length × temperature effect, P<0.01). Experiment 4 evaluated the effects of anticoagulant (SER versus NAF) and whole blood storage (4 °C) for 0, 1, 3, and 7 days on metabolite concentrations. Glucose was higher (P<0.0001) in NAF, possibly the result of the presence of the glycolytic inhibitor, sodium fluoride, whereas l-lactate, NEFA, total cholesterol and β-hydroxybutyrate were higher in SER (P<0.01). Total cholesterol, l-lactate, and NEFA increased, whereas β-hydroxybutyrate decreased with days in storage (P<0.01). Development of hemolysis in the samples artifactually elevated glucose and NEFA values by as much as 41 and 230%, respectively. Attention to proper blood handling, processing, and storage procedures, and avoidance of hemolysis are important in blood clinical analyses and in the proper interpretation of experimental results.     

Parental effects on fertilization and hatching success and development of Atlantic halibut (Hippoglossus hippoglossus L.) embryos and larvae

The parental effects on fertilization and early life history traits were studied in Atlantic halibut, Hippoglossus hippoglossus L. Sperm from 12 different males were used to fertilize eggs of two females in separate crosses. The fertilization success were generally high, above 80% of developing embryos at 16-cell stage in 20 of 24 crosses with an average of 85.9 ± 17.6% and 87.2 ± 16.5% for female A and female B, respectively. Corresponding hatching success was 74.8 ± 17.7% and 41.6 ± 20.1%, respectively. The relationship between fertilization success and hatching success was positive. The parental influence on hatching was dominated by a strong and significant (p < 0.001) maternal effect; however, the paternal effect was also significant (p < 0.001). Furthermore, there was no relationship between fertilization success, hatching success and larvae viability as a high number of larvae developed locked jaws (i.e., were not functional). There was a significant (p < 0.01) difference in yield of functional larvae of female A (43%) and female B (56%), and also between crosses sired by different males. The standard length of offspring of female A (12.4 ± 0.5 mm) and B (12.6 ± 0.6 mm) were significantly (p < 0.001) different, and also significantly influenced by both the female (p < 0.001) and the male (p < 0.001). The present paper provides strong indications that not only the female, but also the male parent influences quantitative features of early development of their offspring.     

Cryoprotective and contraceptive properties of egg yolk as an additive in rooster sperm diluents

The addition of chicken egg yolk to semen extenders is thought to reduce the fertilizing potential of rooster spermatozoa - but not (or at least not as much) that of other avian species. The aim of the present study was to determine whether quail egg yolk, a novel extender additive, provides advantages over chicken egg yolk in the cryopreservation of rooster spermatozoa. Experiments were also performed to determine whether the harmful effect of egg yolk occurs during cryopreservation or during fertilization after artificial insemination. Heterospermic rooster semen samples were divided into aliquots and cooled in a polyvinylpyrrolidone-based medium containing 15% chicken egg yolk, 15% quail egg yolk or no egg yolk at all. The viability of spermatozoa of cooled samples (5 °C) without egg yolk were less viable (P < 0.01) than those of samples containing either type of egg yolk. The same aliquots were then cryopreserved for 15 days. Thawed spermatozoa preserved without egg yolk showed lower motility (P < 0.001) and viability (P < 0.001) than those in samples diluted with either type of egg yolk extender. No eggs were fertilized when hens were inseminated with semen that had been diluted with chicken egg yolk. The fertilization rate was only slightly higher when sperm diluted with quail egg yolk was used (1.5%). The best results were obtained when no egg yolk was used (13.8%). These results show that the addition of egg yolk of either type protects rooster sperm cells against cold shock and during freezing and thawing, but exerts a contraceptive effect in the genital tract of the hen.     

The protective effect of egg yolk from different avian species during the cryopreservation of Karayaka ram semen

Egg yolk is one of the most widely used cryoprotective components for sperm preservation and a wide range of factors affect its action on sperm motility, viability and fertilizing ability. The aim of this experiment was to determine the effect of different species egg yolk, namely the domestic chicken (Gallus gallus domesticus), the goose (Anatidae anser), turkey (Meleagris gallopavo), duck (Anatidae anas platyrhynchos), Japanase quail (Coturmix japonica) and chucker (Alectoris chukar) on sperm quality following cryopreservation of ram semen. Ejaculates were collected using the artificial vagina from three Karayaka rams and spermatological characteristics assessed for the pooled semen. Semen samples were evaluated as split ejaculates in the trial and samples extended with a Tris-citric acid-glucose extender containing the different avian egg yolk (15%) and glycerol (5%). The semen straws were equilibrated at 4 °C for 2 h, frozen in liquid nitrogen vapour (for 15 min at ?120 °C) and stored in liquid nitrogen (?196 °C). After thawing (37 °C for 30 s), sperm motility, viability, abnormal acrosome and membrane integrity (HOST) were evaluated. Results showed chucker egg yolk to have the best cryoprotective effect in terms of the highest sperm motility (54.0%), compared to the other five avian egg yolks (p < 0.05) evaluated. Sperm frozen in chucker egg yolk also showed a higher percentage viability (59%), than sperm stored in quail and turkey egg yolk (p < 0.05). The percentage of acrosomal abnormalities after thawing was lower in the chucker egg yolk, than the other species (p < 0.05). There was no significant difference in sperm membrane integrity between the egg yolks, except for the quail (p < 0.05). Results suggest that chucker egg yolk could be used as an alternative for chicken egg yolk, in a semen extender in cryopreservation, but it warrants further evaluation in fertility trials.     

Adaptive difference in daily timing of hatch in two locust species,Schistocerca gregaria and Locusta migratoria: The effects of thermocycles and phase polyphenism

This study examined the effects of temperature and phase polyphenism on egg hatching time in the desert locust, Schistocerca gregaria, and the migratory locust, Locusta migratoria. The two species exhibited differences and similarities in hatching behavior when exposed to different temperature conditions. In 12-h thermocycles of various temperatures, the S. gregaria eggs hatched during the cryoperiod (low temperature period), whereas L. migratoria eggs hatched during the thermoperiod (high temperature period). The eggs of both species hatched during the species-specific period of the thermoperiod in response to a temperature difference as small as 1 °C. Furthermore, the locusts adjusted hatching time to a new thermal environment that occurred shortly before the expected hatching time. In both species, the hatching of the eggs was synchronized to a specific time of the day, and two hatching peaks separated by approximately 1 day were observed at a constant temperature after the eggs were transferred from thermocycles 3 days before hatching. Eggs laid by gregarious females hatched earlier than those laid by solitarious females in S. gregaria but this difference was not observed in L. migratoria.     

Performance of diapausing parasitoid wasps,Habrobracon hebetor,after cold storage

The ectoparasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae) is an important potential biological control agent for lepidopterous pests of stored products. We investigated the effects of long-term cold storage of diapausing and nondiapausing H. hebetor on their performance after cold storage. Mortality during storage increased with increasing storage duration, and the mortality of diapausing females was lower than that of nondiapausing females after 8, 12, and 16 weeks of storage. Longevity, egg laying, number of progeny produced, and time to 50% egg laying were all reduced, as compared with the culture females when parasitoids were reared at conditions that do not induce diapause. But, for females reared at 20 °C at conditions that induce diapause, all of these quality parameters did not differ from those of culture insects when the storage duration was 8 weeks or less. The percentage of female F1 offspring was always lower for cold stored insects than for the culture insects. Presence of a male after cold storage did not impact any of the quality parameters measured. Thus, rearing parasitoids at 20 °C and 10L:14D and then storing them for up to 8 weeks at 5 °C would produce parasitoids that are similar to culture parasitoids, except that the percentage of females is lower than that in the cultures (36% vs. 52%).     

Egg maturation,oosorption, and wing wear in Gonatocerus ashmeadi (Hymenoptera: Mymaridae), an egg parasitoid of the glassy-winged sharpshooter,Homalodisca vitripennis (Hemiptera: Cicadellidae)

Egg maturation and oosorption in Gonatocerus ashmeadi were investigated in the laboratory and the relationship between hind tibia length (HTL) and <12 h egg load, and wing wear and parasitoid age were determined. G. ashmeadi given access to honey-water and hosts, on average, matured 77 eggs in excess of those they were born with. The number of mature eggs in female G. ashmeadi provided honey-water with no hosts significantly declined after 163 degree-days eggs, while the number of ‘dissolved’ eggs (partially disintegrated mature eggs) increased by nine eggs after 163 degree-days. These results are consistent with oosorption. There was a significant positive correlation between HTL and <12 h egg load. The ovigeny index (the number of mature eggs at female emergence divided by potential lifetime fecundity) for G. ashmeadi was calculated as 0.22 indicating that this parasitoid is a syn-ovigenic species when studied under laboratory conditions. There was a significant positive correlation between wing wear (measured as the number of broken setae per wing) and parasitoid age in the laboratory. The practical implications of these results for G. ashmeadi on the biological control of Homalodisca vitripennis are discussed.     

Quality assessment of Riptortus pedestris (Hemiptera: Alydidae) eggs cold-stored at different temperature and relative humidity regime

Supplementation of host resource can be more economical method for the biological control of insect pest compared to direct release of adult parasitoids. Periodical release of non-viable cold-stored eggs of Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) has been found to enhance parasitism of this pest in soybean fields. To find the optimum environmental conditions for cold storage of these host eggs, we evaluated nine different combinations of temperature (2, 6, and 10 °C) and relative humidity (high 90–95%, medium 70–75%, and low 30–35%). After 30 d of cold-storage, eggs were weighed and held at 26.6 °C and 75% relative humidity for 8 d before testing. To test the eggs’ suitability as hosts following cold storage, females of Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) were released individually onto batches of eggs, and parasitization rates and the development, emergence, sex ratio, adult longevity, and size of parasitoid progeny were examined. Eggs stored at high relative humidity showed less weight loss than those stored at low relative humidity. The number of eggs parasitized was highest (5.9/15) on eggs stored at 6 °C and high relative humidity. Developmental times and adult emergence were optimal on host eggs stored at 2 °C and high relative humidity. A significantly lower proportion of eggs produced male parasitoids when eggs were stored at 2 or 6 °C. Adult longevity was not affected by egg storage conditions, but adult size of progeny decreased in eggs stored at 10 °C. In conclusion, eggs of R. pedestris stored below 6 °C and with a high relative humidity maintained the best quality for parasitization by O. nezarae.     

Differences in egg deposition of corticosterone and embryonic expression of corticosterone metabolic enzymes between slow and fast growing broiler chickens

Glucocorticoids (GCs) are vital for embryonic development and their bioactivity is regulated by the intracellular metabolism involving 11β-hydroxysteroid dehydrogenases (11β-HSDs) and 20-hydroxysteroid dehydrogenase (20-HSD). Here we sought to reveal the differences in egg deposition of corticosterone and embryonic expression of corticosterone metabolic enzymes between slow and fast growing broiler chickens (Gallus gallus). Eggs of fast-growing breed contained significantly higher (P < 0.05) corticosterone in the yolk and albumen, compared with that of a slow-growing breed. 11β-HSD1 and 11β-HSD2 were expressed in relatively higher abundance in the liver, kidney and intestine, following similar tissue-specific ontogenic patterns. In the liver, expression of both 11β-HSD1 and 11β-HSD2 was upregulated (P < 0.05) towards hatching, yet 20-HSD displayed distinct pattern showing a significant decrease (P < 0.05) on posthatch day 1 (D1). Hepatic mRNA expression of 11β-HSD1 and 11β-HSD2 was significantly higher in fast-growing chicken embryos at all the embryonic stages investigated and so was the hepatic protein content on embryonic day of 14 (E14) for 11β-HSD1 and on E14 and D1 for 11β-HSD2. 20-HSD mRNA was higher in fast-growing chicken embryos only on E14. Our data provide the first evidence that egg deposition of corticosterone, as well as the hepatic expression of glucocorticoid metabolic enzymes, differs between fast-growing and slow-growing chickens, which may account, to some extent, for the breed disparities in embryonic development.     

Cold storage of the egg parasitoids Trissolcus basalis (Wollaston) and Telenomus podisi Ashmead (Hymenoptera: Scelionidae)

Adults of Trissolcus basalis and Telenomus podisi were stored either at 15 or 18 °C after their immature development had been completed at 18 or 25 °C. Longevity of the parasitoids in the storage temperatures was evaluated, as well as fecundity and longevity following their return to 25 °C after different periods in reproductive diapause. Temperature during immature development influenced female longevity and highest mean longevity was obtained for females that developed to the adult stage at 25 °C and then were stored at 15 °C (ca. 13 months for T. basalis and 10 months for Te. podisi). For adults of T. basalis that developed at 25 °C, storage periods of 120 or 180 days at 15 or 18 °C did not affect fecundity. The fecundity of T. basalis females that developed at 18 °C and were stored for 120 days at 15 or 18 °C was not affected; however, after remaining for 180 days, fecundity was reduced in ca. 30 and 50%, respectively. Storage of Te. podisi adults at 15 or 18 °C significantly reduced fecundity. It is concluded that adults of T. basalis can be stored in the adult stage at 15 or 18 °C between two soybean crop seasons for mass production purposes, aiming the biological control of stink bugs.     

Incubation temperature affects hatching success,embryonic expenditure of energy and hatchling phenotypes of a prolonged egg-retaining snake,Deinagkistrodon acutus (Viperidae)

We used eggs of Deinagkistrodon acutus to study the effects of incubation temperature on hatching success, embryonic expenditure of energy and hatchling phenotypes. One egg from each of the 15 fertile clutches was dissected for determination of egg composition, and a total of 164 eggs were incubated at five constant temperatures. Embryonic mortality increased dramatically at 30 °C, and none of eggs incubated at 32 °C hatched. Within the range from 24 to 30 °C, temperature affected incubation length and most hatchling traits examined. The mean incubation length at 24, 26, 28 and 30 °C was 36.4, 28.7, 21.8 and 15.7 days, respectively. Embryos developing at higher temperatures (28 and 30 °C) consumed more energy but produced less developed (and hence smaller) hatchlings, which characteristically had larger residual yolks but smaller carcasses. A principal component analysis resolved two components (with eigenvalues ⩾1) from ten size (initial egg mass)-free hatchling variables, accounting for 79.3% of variation in the original data. The first component (43.8% variance explained) had high positive loading for size-free values of dry mass, lipid mass, energy contents and ash mass of hatchlings, and the second component (35.5% variance explained) had high positive loading for size-free values of SVL, carcass dry mass and fatbody dry mass. Hatchlings from different incubation temperatures did not differ in scores on the first axis of the principal component analysis, whereas hatchlings from higher incubation temperatures (28 and 30 °C) had significantly lower scores on the second axis than did those from lower incubation temperatures (24 and 26 °C). As the second axis mainly represents traits relating to the developmental condition at hatching, the analysis therefore provided further evidence that eggs incubated at higher temperatures produced less developed hatchlings. Taken together, our data show that the optimal temperatures for embryonic development are relatively low in D. acutus largely due to its use of relatively cool habitats.     

Seeding experiments demonstrate poor performance of the hatching test for detecting small numbers of Schistosoma mansoni eggs in feces

Parasitological methods for the evaluation of schistosomiasis tend to be limited when parasitic burdens are low, which is a major characteristic of low intensity transmission areas. While the hatching test (HT) method has been considered to be “very sensitive”, reports of its capacity to detect low numbers of eggs remain scarce in the published literature. Our main hypothesis is that HT has limitations and cannot be recommended for diagnosing light infections or as a control of cure. Hence, this study aims to describe the performance of HT in detail, with respect to seeding experiments for egg numbers in the range of 4 to 24 eggs per gram (epg) of feces. Different numbers of eggs of Schistosoma mansoni were seeded in normal human feces. The first set of experiments evaluated the amount of feces (higher than 0.5 g prevented hatching), the proximity of the light source (50 cm was preferred), and the observation time required for the detection of miracidia (more than 3 h did not add to sensitivity). HT was subsequently performed with 12, 10, 8, 6, 4, and 2 eggs in 0.5 g of feces. The final set of experiments was performed to analyze the initial filtration step, in which surgical gauze versus a 500 μm nylon mesh was compared and demonstrated losses of eggs that occurred with washing and gauze (better with nylon) sieving steps. The proposed method was found to produce 100% positivity for up to 12 epg, with a sharp decrease to 33% for 8 epg and less. In conclusion, HT is not recommended for diagnosing intestinal schistosomiasis in populations with light infections, considering the complexity of the procedure and its lack of effectiveness with fecal amounts higher than 0.5 g even at optimized conditions.     

Effect of cyclical cold stress during embryonic development on aspects of physiological responses and HSP70 gene expression of chicks

The objective of the present study was to evaluate the effects of cyclical lower incubation temperature at different embryonic ages on the hatchability, body and organs weights, thyroid hormones, and liver HSP70 gene expression of newly hatched chicks. In a completely randomized design, fertile eggs of a broiler breeder (34 weeks of age) were assigned to three treatment groups with six replicates and 145 eggs per each. The treatment groups were as: control group (C) that eggs were incubated at 37.6 °C during the whole incubation period; incubation temperature was decreased to 36 °C for 3 h per day at embryonic age from 12 to 14 (T1); and incubation temperature was decreased to 36 °C for 3 h per day at embryonic age from 15 to 17 (T2). No significant difference was found among treatments for hatchability (P>0.05). There were no differences (P>0.05) among treatments for body weight and liver weight, while heart weight of chicks in T1 and T2 groups were significantly higher than the control group (P<0.05). There were no differences (P>0.05) among treatments for the levels of thyroid hormones, however, the levels of both hormones tended to increase in chicks exposed to cold stress (T1 and T2). Chicks in T2 group had higher liver HSP70 gene expression compared with those in T1 and the control group (P<0.05). Cold stress in both incubation periods had no significant effect on the plasma levels of aspartate aminotransferase and alanine aminotransferase. Treatments had no effect on the plasma levels of glucose, cholesterol and triglyceride. The results of this study suggest that cyclical lower incubation temperatures (36 °C) at the embryonic age from day 15–17 could induce the liver HSP70 gene expression, without negative effects on the hatchability and body weight of hatched chicks.     

Dietary inclusion of raw faba bean instead of soybean meal and enzyme supplementation in laying hens: Effect on performance and egg quality

An experiment was conducted with 160 Hisex Brown laying hens to evaluate the effect of different inclusion levels of faba bean (FB) and enzyme supplementation on productive performance and egg quality parameters. The experimental diets consisted of five levels of FB: 0% (control), 25%, 50%, 75% and 100%, substituting soybean meal (SBM), and two levels of enzyme supplementation (0 or 250 mg/kg). Each dietary treatment was assigned to four replicate groups and the experiment lasted 22 weeks. A positive relationship (P < 0.05) was found between FB inclusion and body weight (BW) change of hens when compared to those of the control treatment. Enzyme supplementation significantly affected the final hens’ BW. Feed consumption (FC) of hens was statistically increased with increasing FB level up to 50%. Supplementing dietary enzyme mixture at 250 mg/kg led to improvement in FC at all studied ages (P < 0.05). Inclusion of 25% or 50% FB in diets had no adverse effects on feed conversion ratio (FCR) compared to the higher FB inclusion levels (75% or 100%). Egg weight (EW), egg number (EN) and egg mass (EM) were significantly (P < 0.05) influenced by FB inclusion in diet during the entire experimental periods, except for EN and EM at 20–24 weeks of age. Egg productive parameters were not influenced by enzyme mixture supplementation (P > 0.05). The main effect of FB levels replacing for SBM affected (P < 0.05) yolk and shell percentages, yolk index, yolk to albumen ratio, shell thickness and egg shape index. It can be concluded that FB and enzyme supplementation could be included in hens diet at less than 50% instead of SBM to support egg productive performance, however higher raw FB levels negatively affected egg production indices and quality.     

Control the egg hatchling process of Pomacea canaliculata (Lamarck) by water spraying and submersion

Pomacea canaliculata (Lamarck) is an invasive snail species that has become a serious pest of rice and other hydrophytes. Usually it is aquatic but likes to lay its eggs higher than the waterline. In order to seek a feasible and efficient way to control the egg hatchling of this pest, here we systematically studied the effects of water spraying and submersion on its egg hatchling rates and durations. Our results demonstrated that water spraying and submersion could dramatically decrease the hatchling rates to maximal 5.8% and increase the hatchling duration up to 26.4 days on P. canaliculata. Not only the beginning time of water treatment, but also the frequencies of the water spraying is critical to control the hatchling rate and duration of P. canaliculata. Water submersion that began in 12 h after the eggs laid and lasted at least 48 h will significantly decrease the snails’ hatchling rates and extend the hatchling time. In addition, compared to spraying, the water submersion could achieve more remarkable effects. The capsule of the snail’s egg is able to withstand the water treatment. Based on our water spraying and submersion results, it can be inferred that 0–6 h after egg being laid, egg capsule precipitates are beginning to form, and this process will complete after 12–24 h. This special breeding characteristic of P. canaliculata makes the physical control by water treatment become feasible.     

Effect of storage temperature and duration on viability of eggs of Helicoverpa armigera (Lepidoptera: Noctuidae)

The ability to store different insect stadia for prolonged periods provides considerable flexibility and ability to conduct experiments properly. Therefore, studies were undertaken to determine the effect of storage temperature and duration on viability of eggs of Helicoverpa armigera (Hübner). The percentage egg hatch and incubation period were significantly (P=0.01) influenced by egg age, storage temperature, and storage duration. Egg hatch ranged from 0.0 to 96.8% across temperatures and storage durations. None of the eggs hatched when stored at -20 and 0 degrees C. The regression model with the optimum Mallow Cp statistic for any of the identified linear and quadratic terms did not improve the precision of prediction in egg hatch beyond 67.0%. Forecasting of incubation period based on egg age, storage duration, and durationxtemperature was quite effective (R2=84.2%). Day degrees required for egg hatching decreased with an increase in temperature from 10 to 27 degrees C, and egg age from 0 to 3 days. The day degree requirements were highest for 0-day-old eggs at 10 degrees C, and lowest at 27 degrees C. Although the incubation period was higher, the hatchability was lower for 0- and 1-day-old eggs stored at constant 10 degrees C, these eggs can be stored for 10 days at 10 degrees C, with a hatchability of >75.0%. It was safer to store the H. armigera eggs for 10 days at 10 degrees C, which will hatch within 1.6 to 2.0 days after restoration at 27 degrees C with a hatchability of >75.0%. This information will be useful in planning and execution of experiments involving H. armigera on various aspects of research in entomology.     

Effect of weight and storage time of broiler breeders’ eggs on morphology and biochemical features of eggs,embryogenesis, hatchability,and chick quality

The transfer of hatchability results obtained under experimental conditions to the commercial ground with a positive financial effect proves the value and usefulness of these data. On the other hand, finding results on commercial processes of broiler breeders’ egg incubation in the literature is challenging. The presented study aimed to determine the effects of egg weight and storage time on the physical, biochemical characteristics of hatching eggs, embryogenesis and hatchability in Ross 308 broiler breeders. On the laying day, the eggs were divided into four weight groups: S – small eggs (57–61 g), M – medium eggs (62–66 g), L – large eggs (67–71 g), and XL – extra-large eggs (72–76 g). The eggs were then stored for 3, 7, 14, and 21 days under controlled conditions. As the egg storage time increased, a decrease in the yolk quality (lower index) was observed. The highest Haugh units were found in eggs from the S and M groups. The cholesterol content of the M, L, and XL groups was lower on days 7, 14, and 21 as compared to that of eggs only stored for 3 days. Egg weight loss during incubation decreased with an increase in the egg weight. An extension of the egg storage time caused an increase in the loss of egg weight. On the 14th and 18th days of hatching, an increase in the eggshell temperature was noted with an increase in the weight of the egg. The eggs stored for 7 days were characterised by the highest shell temperature on each day. The highest hatchability percentage was recorded for the M group. The hatchability rate decreased with the prolongation of the storage time, while the number of crippled chicks after hatching increased. The results confirmed that the increased weight of the eggs and prolonged storage time (14 and 21 days) increased the weight and decreased the length of the newly hatched chicks, respectively. Chicks from the heaviest eggs and those stored for 14 and 21 days showed poor results on the Pasgar score® test. The observations indicate the need to adopt various (of those available) methods to assess the quality of newly hatched chicks in hatcheries in order to produce high-quality broiler chickens. The results also indicate that prolonged egg storing beyond 14 days may affect the thyroid hormone economy during the hatching of chicks, especially in the XL group.     

Effect of simultaneous variation in temperature and ammonia concentration on percent fertilization and hatching in Crassostrea ariakensis

The combined effects of temperature and ammonia concentration on the percent fertilization and percent hatching in Crassostrea ariakensis were examined under laboratory conditions using the central composite design and response surface methodology. The results indicated: (1) The linear effects of temperature and ammonia concentration on the percent fertilization were significant (P<0.05), and the quadratic effects were highly significant (P<0.01). The interactive effect between temperature and ammonia concentration on the percent fertilization was not significant (P>0.05). (2) The linear effect of temperature on the percent hatching was highly significant (P<0.01), and that of ammonia concentration was nonsignificant (P>0.05). The quadratic effects of temperature and ammonia concentration on the percent hatching were highly significant (P<0.01). The interaction on the percent hatching was not significant (P>0.05). Temperature was more important than ammonia in influencing the fertilization and hatching in C. ariakensis. (3) The model equations of the percent fertilization and hatching towards temperature and ammonia concentration were established, with the coefficients of determination R²=99.4% and 99.76%, respectively. Through the lack-of-fit test, these models were of great adequacy. The predictive coefficients of determination for the two model equations were as high as 94.6% and 98.03%, respectively, showing that they could be used for practical projection. (4) Via the statistical simultaneous optimization technique, the optimal factor level combination, i.e., 25 °C/0.038 mg mL⁻¹, was derived, at which the greatest percent fertilization 95.25% and hatching 83.26% was achieved, with the desirability being 97.81%. Our results may provide advantageous guidelines for the successful reproduction of C. ariakensis.