Earticle

가금 산업에 있어서 닭 정액의 희석은 저온 저장과 동결 보존에 있어 매우 중요한 과 정이며 농가 간 정액의 교류를 통한 산업적 이용성이 높은 연구 영역으로 판단된다. 그 럼에도 불구하고 닭 정액의 희석에 관한 연구는 미진한 편이며, 정액의 희석 비율 또한 4~8배에 머물고 있어 소와 같은 포유류에 비하여 많이 낮은 편이다. 본 연구에서는 닭 정액의 희석 비율을 높이기 위하여 fatty acid free BSA (FAF-BSA) 0.1%을 첨가한 BPSE 희석액을 이용하여 레그혼의 신선 정액을 10배 희석하였다. 희석된 정액을 17℃에 서 6시간 저온 보존한 후, 인공수정을 실시하였다. 수정 후 10일 동안 회수한 수정란을 37.8℃ 배양기에서 발육시켰으며 발생 5일자 수정란에서 수정률을 조사하고 발생 19일에 하란을 실시여 21일에 수정란의 부화율을 조사하였다. 대조군으로 BSA를 0.1%가 함유된 BPSE를 이용하고 동일하게 보존하여 인공수정을 실시하였다. FAF-BSA를 활용한 실험군 에서 수정률이 유의적 수준으로 증가하였으며(53.2% vs. 38.3%, p<0.05), 부화율 또한 증가하였다(90.9% vs. 78.33%, p<0.05). 이러한 결과는 FAF-BAS를 활용하여 닭 정액을 희석하고 저온 저장할 때 그 이용성과 효율성이 증가한다는 것을 보여주고 있으며 닭 정 액이 필요한 농가와 종계의 정액을 이용하고자 하는 농가에서 그 활용성이 높을 것으로 판단된다.

The objective of this study was to analyze the reproductive ability by strains and age in weeks of Korean native chicken and to compare the egg weight by body weight of Korean native chicken cock. Six strains (L=black, W=white, O=Ogol chicken, G=gray, R=red, and Y=brown) of Korea native chicken were used in this study. The fertility of strains W and Y were 89.6% and 86.3% respectively, and significantly higher than the other strains (p<0.05). Strains R and W showed high hatchability (90.7%, 89.6%, respectively) and strains L and O showed low rate (78.9%, 87.3%, respectively). There was no significant difference by weeks in each strain. The fertility was the highest at 28 weeks of age and the hatchability showed the highest value at 26 weeks of age. Egg weights of strains L and R were significantly high (p<0.05) but strains W and G were significantly low (p<0.05). Egg weight was higher in 1.65 ㎏ of Korea native chicken cock than in 2.00 ㎏ of Korea native chicken cock. These results suggest that the using average weight (1.65 ㎏) of Korea native chicken cocks could have an advantage for the feed cost savings and productivity improvement.

This study was carried out to investigate the effects of semen on reproductive ability in crossbred Korean native chicken (KNC, 58-wk old). The body weight, volume of semen and concentration of spermatozoa, were 2.96 g, 0.40 ml, 36.58×108/ml, respectively, in KNC. The fertility and hatchability were 94.8% and 78.8% respectively in crossbred KNC. KNC(Y) was high compared to other strains in fertility. The other strains were not significantly different among 6 strains. The results of this experiment indicated that hatchability of (G) was high compared to other strains. The result of this study could be available to genetic improvement of reproductive traits as a basic reference in KNC strains. To achieve the more effective improvement of reproductive traits, addition research such as genetic parameter evaluation should be performed.

The objective of this experiment was to investigate the effects of in ovo feeding of arginine (Arg), tryptophan (Trp), and threonine (Thr) on hatch performance, hatchability, and morphometry of newly hatched broiler chickens. A total of 400 fertile eggs from 28-week-old Arbor Acres broiler breeder flocks, with an average fertile egg weight of 52 ± 0.7 g, were collected for the experiment. The eggs were randomly assigned to five treatment groups (80 eggs per group, eight replicates of 10 eggs each): non-injected control (CON); phosphate-buffered saline (PBS) injection (100 μL of 1% PBS); Arg injection (100 μL/egg); Trp injection (100 μL/egg); and Thr injection (100 μL/egg). All eggs were incubated at the recommended temperature and humidity of 38.0 ± 0.2℃ and 75.0 ± 3%, respectively. After hatching, one 1-day-old broiler chick per replicate with a body weight (BW) close to the average of each treatment was selected for hatchability and morphometry assessments. Results indicated that CON and PBS groups had significantly greater (p < 0.05) BW than Trp and Thr groups. The hatch window was greater (p < 0.05) in Thr group compared to CON, PBS, and Trp groups. However, no significant differences were observed among treatments for hatchability such as hatch of set and fertile, egg weight, survival rate, and chick yield. Morphometric analysis revealed that Arg, Trp, and Thr treatment groups exhibited significantly greater (p < 0.05) middle toe length compared to CON group. Conversely, small intestine length and chick body length were reduced (p < 0.05) in Arg, Trp, and Thr groups compared to CON group. No significant differences were observed in tibia and radius among groups. In conclusion, in ovo feeding Arg, Trp, and Thr influenced chick morphology and organ development, indicating that precise dosage optimization of amino acid injection during the embryonic stage is essential.

In this study, the embryonic development and hatchability of eggs fertilized by the reciprocal hybrids of kelp grouper (Epinephelus bruneus) and red-spotted grouper (E. akaara) were evaluated with the goal of establishing a novel hybrid with enhanced growth and viability during the farming period in the temperate waters of Korea. The fertilization rates were lower for hybrids than for maternal purebreds and were significantly higher in the red-spotted grouper ♀ × kelp grouper ♂ hybrid (RGKG, 89.61 ± 1.58%) than in the kelp grouper ♀ × red-spotted grouper ♂ hybrid (KGRG, 74.82 ± 4.23%, p < 0.05). Unlike the fertilization rates, the hatching rates of fertilized eggs were similar between hybrids and maternal purebreds and did not differ significantly between KGRG and RGKG (72.74 ± 3.60% vs. 75.23 ± 2.20%, respectively, p > 0.05). The embryonic development of the hybrids was similar to that of maternal purebreds; however, irregular cleavage and asymmetric blastoderm were noticeable in the developing eggs of KGRG hybrids. The deformity rates of newly hatched larvae were higher in hybrids than in maternal purebreds and were significantly higher in KGRG than in RGKG (17.47 ± 1.28% vs. 7.11 ± 0.54%, respectively, p < 0.05). These results demonstrate the potential to produce viable larvae from these two hybrids. Although the production efficiency of KGRG was lower than that of RGKG, the fertilization, hatching, and deformity rates make both hybrids useful for further comparative studies regarding economic aspects.

The cadmium (Cd) toxicological effects on the fertilized eggs, embryos and larvae were investigated in olive flounder, Paralichthys olivaceus water-borne exposed to Cd. The survival rate and hatching success of the embryos significantly diminished in treated groups in dependence of the Cd concentration. Significant differences were found at ${\geq}30{\mu}g\;L^{-1}$ exposed groups compared to the control group. A significant increase of malformation of the embryo was observed at ${\geq}20{\mu}g\;L^{-1}$ exposed groups. They usually include such symptoms as clouded yolk-sac abnormality, fin erosion and spinal curvature. A significant reduction in the survival rate of the larvae was observed in ${\geq}20{\mu}g\;L^{-1}$ exposed groups with accompanied by the disorder. Notably, in larvae, a concentration as low as $10{\mu}g\;L^{-1}$ exposed groups caused significant elevated abnormalities that is incidences of spinal cord deformation, abnormal eyes, deformation of the head region and severe developmental delay.

The effects of dark-control (D) and continuous green light (GL) exposure of incubated meat-type breeder eggs (Hybro) on embryonic growth from 5 to 15 days of age, hatching time, hatchability per cent and chick hatching weight were investigated in three consecutive experiments at 33, 38, and 41 weeks of age. A total of 798 eggs were used in this study. Eggs were set in an incubator on trays either in the D or under two tubes of 20-watt green fluorescent light during the first 18 days of incubation. Eggs from both treatments were transferred to the dark hatching compartment at 19 days of incubation. The light intensity was in the range of 1,340 to 1,730 lux at the surface of the eggs. GL incubation of eggs significantly (p<0.01) increased weight (expressed as an absolute value) and daily weight gain of embryos at 11 and continued to 15 days of age, hatchability per cent by 4.8%, reduced dead embryos per cent and chick weight at hatch by 37 and 2%, respectively and accelerated hatching time by about 24 h when compared with the D-control incubation. Chicks hatched at 504 h of incubation had significantly (p<0.01) higher body weight, expressed as an absolute value or as a percentage of egg weight, than those hatched earlier at 456 h of incubation. It was concluded that the GL incubation of meat breeder eggs reduced incubation period and chick weight at hatch and increased embryonic growth and hatchability per cent.

The rate of oxygen consumption of the silkworm eggs was measured to set up the barometer for measuring the effect of egg chilling on diapause termination. In diapause eggs, $O_2$ uptake showed a maximum of 79.2 ${mu}ell$/mg eggs/hr, at one day after oviposition and then gradually decreased to 2.2${mu}ell$/mg eggs/hr at 9days. The rates of oxygen uptake of eggs raised immediately after HCl-treatment and reached to a maximal level of 484.5 ${mu}ell$/mg eggs/hr in 9-day-old eggs, which corresponds to 220 fold that of diapause eggs, and the hatching ability was also over 50％. In order to break diapause, eggs incubated at $25^{\circ}C$ for 30 days after oviposition had to be kept at least for 45 days at 5$^{\circ}C$, but chilled eggs for 90 days or longer hatched at 10 days as normal hatching periods. We also investigate periods which the value of $O_2$ uptake of eggs chilled during 15 to 120 days at 5$^{\circ}C$ reached at 200 ${mu}ell$/mg eggs/hr. As a result of that, $O_2$ uptake of eggs chilled during 15 to 45days were not reached at 200 ${mu}ell$/mg eggs/hr and longer the chilling durations are, the higher the rate of $O_2$ uptake is and the longer the chilling durations are, the shorter the periods up to hatching is. And also, hatch-ability increased rapidly as $O_2$ uptake reaches over 20/eggs/hr.

Eggs obtained from 46 and 42 weeks old meat (Hybro) and layer (Leghorn) breeders flocks, respectively were used to examine the effects of genetic type of birds and egg size (small, medium and large) on variables of eggshell characteristics and hatchability traits. The variables measured were egg weight (EW), egg surface area (ESA) and eggshell characteristics (shell conductance (EC), per cent shell (PS), shell thickness (ST), shell volume (SV), shell density (SD) and hatchability traits (per cent hatchability (HP), early dead embryos (ED), late dead embryos (LD), pips with live embryos (PL) and pips with dead embryos (PD)). Genetic type of bird influenced all egg characteristics and HP of eggs. Eggs produced by the small Leghorn bird had lower EW, ESA, EC, ST, SV and HP than those produced by the heavy Hybro bird. The reduction of HP was associated with an increase in the percentage of ED and PL. Egg size influenced all variables measured except ST. Small size eggs had lower EW, ESA and EC and higher PS and SD than those of large eggs. Medium size eggs produced a higher HP when compared with that of large size eggs. The reduction of HP in large eggs was associated with higher percentage of ED, LD and PL. There were significant interactions between the genetic group of birds and egg size on LD and HP. Large egg size of Hybro birds had higher LD and lower HP than those of small size eggs produced by the same flock. However, There was no difference in HP and LD among the different egg sizes produced by Leghorn birds. It was concluded that genetic make up of birds and egg size influence eggshell characteristics and HP. The type of bird (heavy or small) influences the optimum egg size for successful hatching. Attention should be given to the size and eggshell characteristics of eggs of breeders' flocks for achieving maximum HP.

Hexavalent chromium (CrVI) was fed to one day old chicks of Gallus domesticus in the form of different concentrations (250 and 500 mg/kg feed) of potassium dichromate mixed with the feed, ad libitum, for 32 weeks. After 20 weeks of feeding, the total body weight was higher in the low dose (260 mg/kg (feed) group and lower in the high dose (500 mg/kg feed) group, as compared with the control chicks. After 32 weeks of feeding, however, the total body weight was significantly decreased in both the treated groups. Egg laying was enhanced. Fertility remained unaffected, whereas hatchability was considerably decreased after CrVI-treatment. The egg shell thickness increased significantly (13%). Cr was deposited in a dose dependent manner in the liver and lungs. Some structural derangements in liver were also noted in treated chicks. The results of this study i.e., rapid ageing, excessive Cr deposition, decreased hatchability and hepatotoxicity indicate toxic effects of CrVI.

The present study aimed to determine the effects of different storage materials and storage period on some hatchability traits of Japanese quail (Coturnix coturnix japonica) eggs. A total of 32 male and 102 female quail (twelve weeks of ages) were housed in multiple-bird cages. Eggs laid were divided into three groups with respect to the period of storage (I = 1st, 2nd and 3rd days, II = 6th, 7th and 8th days, III = 12th, 13th and 14th days) prior to incubation. A total of 816 eggs was stored in 3 different storage environments during each storage period (B = no use of any storage material, P = use of perlite, H = use of hay) and kept in environmental conditions, where the temperature was $21^{\circ}C$ and relative humidity was 75%, prior to incubation. Statistical analyses were performed after the exclusion of values pertaining to non-fertile eggs (190 eggs) from the data set. The fertility rate of the eggs in the experiment was 76.7%. In the present study, the influence of storage material and different storage periods on egg weight loss were found to be statistically significant (p<0.01). Upon the comparison of hatchability of fertile eggs values, the influence of storage material was determined to be significant (p<0.05), and the influence of storage period was demonstrated to be significant (p<0.01). The storage materials used were determined not to have any influence on early and late embryonic death rates. Perlite was concluded to be safe for use in the storage of hatching eggs. The extension of the storage period (more than 8 days) resulted in decreased hatchability values of fertile eggs in each group.

One thousand and eighty eggs of Japanese quail (Coturnix coturnix Japonica) were set into the incubator maintaining 36 treatment groups (3 egg weight groups ${\times}3$ seasons ${\times}4$ preincubation holding periods) to evaluate their hatchability performances. Holding periods had significant (p<0.05) effect on hatchability and the seasons showed significant (p<0.05) effect on chick weight. All the parameters (except fertility) were significantly (p<0.01) influenced by the egg weight. None of the parameters maintained regular trend with egg weight and pre-incubation holding periods. Significant interactions were not observed on any of the parameters (except fertility) studied. The egg weight maintained significant (p<0.05) negative correlation with fertility and positive correlation with chick weight. Eggs of medium weight (9.10 to 10.00 cm) could be hatched satisfactorily between 4 and 7 days of pre-incubation holding periods in any season of the year.

Objective: This study was conducted to compare morphological defects, viability, motility (MOT), fertility (F), and hatchability (H) in four Korean native chicken breeds (KNCBs), and to evaluate whether defective segments of spermatozoa are associated with MOT, F, and H. Methods: Four KNCBs, including Korean Ogye (KO), Hwangbong (HB), Hyunin Black (HH), and Hoengseong Yakdak (HY) were used. White Leghorn (WL) was used as a control. Nine cocks from each breed were randomly assigned into three groups. Semen was collected by abdominal massage method. Eosin-nigrosin staining method was used to identify live-dead spermatozoa. Different segments and specific morphological defects of spermatozoa were identified using 4', 6-diamidino-2-phenylidole and MitoTracker Red CMXRos. F and H rates were evaluated following artificial insemination (AI). Results: KO had the highest MOT rate compared to HY. Viable normal sperm rates of KO and HH were high and comparable with WL. HY spermatozoa had the highest viable abnormal sperm (VAS) or morphological defect rate followed by HB. Likewise, HB spermatozoa had the highest dead sperm (dead) rate compared to KO, HY, and WL. Bent, coiled, detached, broken, and knotted were common identified specific morphological defects for all breeds. Most morphological defects were at the head and tail in all breeds. VAS showed strong negative correlation with MOT (r = -0.697) and F (r = -0.609). Similarly, defective tail was negatively correlated with MOT (r = -0.587), F (r = -0.797), and H (r = -0.448). The F and H rates of KO and WL were comparable. Conclusion: These data indicate that most identified specific morphological defects are at the head and tail. VAS and defective tail were associated with poor motility, F, and H. KNCBs showed more morphological defects than WL. Finally, these results will facilitate successful AI and semen cryopreservation.

The effect of adding transparent fluid (TF) to fowl semen on fertilizing capacity of fowl spermatozoa and on hatchability was studied. Diluted semen and semen containing 15% TF were stored for 24 h at $3-5^{\circ}C$ and inseminated at weekly basis for 5 consecutive weeks. No significant differences were observed in fertility, hatchability and embryonic mortality among the treatments. The results suggest that TF is not necessarily detrimental to fowl spermatozoa even when mixed with semen and stored outside the body.

The objective of this experiment was to investigate the effects of in ovo feeding of arginine (Arg), tryptophan (Trp), and threonine (Thr) on hatch performance, hatchability, and morphometry of newly hatched broiler chickens. A total of 400 fertile eggs from 28-week-old Arbor Acres broiler breeder flocks, with an average fertile egg weight of 52 ± 0.7 g, were collected for the experiment. The eggs were randomly assigned to five treatment groups (80 eggs per group, eight replicates of 10 eggs each): non-injected control (CON); phosphate-buffered saline (PBS) injection (100 µL of 1% PBS); Arg injection (100 µL/egg); Trp injection (100 µL/egg); and Thr injection (100 µL/egg). All eggs were incubated at the recommended temperature and humidity of 38.0 ± 0.2℃ and 75.0 ± 3%, respectively. After hatching, one 1-day-old broiler chick per replicate with a body weight (BW) close to the average of each treatment was selected for hatchability and morphometry assessments. Results indicated that CON and PBS groups had significantly greater (p < 0.05) BW than Trp and Thr groups. The hatch window was greater (p < 0.05) in Thr group compared to CON, PBS, and Trp groups. However, no significant differences were observed among treatments for hatchability such as hatch of set and fertile, egg weight, survival rate, and chick yield. Morphometric analysis revealed that Arg, Trp, and Thr treatment groups exhibited significantly greater (p < 0.05) middle toe length compared to CON group. Conversely, small intestine length and chick body length were reduced (p < 0.05) in Arg, Trp, and Thr groups compared to CON group. No significant differences were observed in tibia and radius among groups. In conclusion, in ovo feeding Arg, Trp, and Thr influenced chick morphology and organ development, indicating that precise dosage optimization of amino acid injection during the embryonic stage is essential.

Objective: The present trial was conducted to determine the influence of different dietary fatty acid (omega-3 and omega-6) sources on reproductive performance of female broiler breeders and growth performance and carcass traits of their progeny. Methods: Two hundred and twenty, 25 weeks old Ross-308 male (20) and female (200) broiler breeders were used in the experiment for the period of 6 weeks. All birds were randomly divided into four dietary treatments (containing 2% soybean oil, 2% sunflower oil, 2% flaxseed oil, and 2% fish oil) each with five replicates of one male and ten females. Throughout this experiment hatching performance of broiler breeders, progeny growth performance and carcass parameters were recorded. Results: The results showed that the inclusion of different fatty acid sources in female broiler breeders diet had no significant effects (p>0.05) on number of fertile eggs, post-hatch mortality, and fertility rate. The soybean oil supplemented group had significantly (p<0.05) higher late embryonic mortality compared to other three treatments. Conclusion: It was concluded that inclusion of 2% of different sources of omega-3 and omega-6 fatty acids (especially 2% flax seed oil) in broiler breeders' diet can reduce late embryonic mortality. The other reproductive characteristics of parents and growth and carcass characteristics of progeny remained unaltered by dietary sources of omega-3 and omega-6 fatty acids.

The effects of controlled energy restriction and duration of pre-incubation egg holding on fertility, hatchability and hatch losses were evaluated in aged broiler breeders (64 wk). The energy (ME) required for maintenance, activity, growth and anticipated egg production was calculated and offered to a control group (283-471 kcal/kg) from 21-64 weeks of age. In three other groups, ME was quantitatively reduced either by 20% (SER; severe energy restriction) or 10% (MER; moderate energy restriction) and increased by10% (EEF; excess energy feeding) over the control group (CER; controlled energy restriction). Each diet was offered to 130 pullets in individual cages, and the quantity of ME increased with age. At the end of 64 weeks, fertile eggs were collected from each dietary group for 11 consecutive days and grouped under 4 holding periods based on the length of storage (2, 5, 8 or 11 d). The influence of energy regimes, egg holding intervals and their interaction was evaluated on fertility, hatch losses and hatchability. Broiler breeders maintained on SER regime (231-419 kcal/d) produced maximum number of eggs (993) followed by MER (819), CER (624) and EEF (438) during the 11-day period. The percent fertility and hatchability was significantly (p$\leq$0.05) higher in SER and MER groups compared to CER and EEF. However, energy regimes did not influence the loss in egg weight during pre-incubation storage, shell weight, shell thickness or hatch losses as dead germs and dead in shell. The improvement in hatchability in SER and MER groups appeared to be closely related to higher fertility and lower embryonic mortality. Holding of eggs for 11 days showed a linear loss in egg weight with the length of storage, but did not influence the fertility and hatch losses. The percent hatchability on eggs set was maximum when storage period was restricted to 5 days. The interaction between energy regimes and egg holding periods exhibited better hatchability results with SER regime when eggs were held for 5 days. Response to MER was not different from SER. It was obvious that energy restriction during production period had a positive influence on egg number, fertility and hatchability in aged breeders. At 64 weeks of age, holding of fertile eggs for 5 days prior to incubation was adequate for optimum hatchability in breeders.