A third allele at the phosphoglucose isomerase locus of the Japanese quail

Phosphoglucose isomerase electrophoretic patterns of the Japanese quail were found to be controlled by three alleles at an autosomal locus. In the laboratory quail population, the frequency of the alleles PGI^F, PGI^S1 and PGI^S2 was 0.175, 0.465 and 0.360, respectively.     

Early development of milkfish: effects of salinity on embryonic and larval metabolism, yolk absorption and growth

During embryogenesis of Chanos chanos , more than half of the yolk was consumed and the majority of it was converted into larval tissue. Salinity affected both yolk absorption and embryonic and larval growth. Larvae hatched in 20% had larger yolk reserves but were smaller and grew more slowly than larvae in 35 and 50%. Larvae hatched in 35 and 50% had equal amounts of yolk but those from 35% were larger. Oxygen consumption rates increased during development (from 0.06 ± 0.01 μl O₂ egg^–1 h^–1 by blastulae to 0.37 ± 0-01 μl O₂ egg^–1 h^–1 by prehatch embryos and 0–43 ± 0–03 μl O₂ larva ^–1 h ^–1 by newly-hatched larvae) and were significantly affected by salinity. Eggs and yolk-sac larvae incubated in 35% consumed more oxygen than those in the low and high salinities. Salinity affected both the rate and pattern of yolk utilization but salinity-related differences in metabolism, yolk absorption, and growth were not related directly to the osmotic gradient. Low salinity retarded yolk absorption while high salinity reduced yolk utilization efficiencies. Differences in oxygen consumption rates were probably related to variations in the relative amounts of metabolically active embryonic and larval tissue and/or higher activity levels rather than differential osmoregulatory costs. 35% is probably the most suitable salinity for incubation and larval rearing of milkfish.     

Genetical control of phosphoglucose isomerase isozymes in the Japanese quail erythrocytes

Three phenotypes of phosphoglucose isomerase (PGI) from the Japanese quail erythrocytes were observed by horizontal starch gel electrophoresis. Population and family data from one laboratory population of quail was consistent with the theory that PGI polymorphism was controlled by two codominant, autosomal alleles designated PGI^F and PGI^S with gene frequency values 0.25 and 0.75, respectively. The study supported the earlier view that the Japanese quail is highly polymorphic with regard to biochemical variation.     

Genetic control and population survey of transferrin in the Japanese quail

Transferrin types in the Japanese quail Coturnix coturnix japonica are controlled by a single autosomal locus Tf with at least two codominant alleles Tf^B and Tf^c. The frequencies of Tf^B and Tf^c in a commercial population of the domestic quail were 1.00 and 0.00, respectively.
Previous studies demonstrated that in the domestic populations of the Japanese quail three electrophoretic patterns AB, B and BC existed in egg white conalbumin and that the electrophoretic variation of conalbumin occurred in parallel with that of serum transferrin. Furthermore, from the preliminary mating experiments the transferrin-conalbumin variation was proposed to be under the control of at least two codominant alleles 77^s and Tf^c at an autosomal locus (Kimura et al., 1977, 1978).
The present study was designed (1) to report a large amount of family data from three generations in order to support the previously published hypothesis on genetic control of electrophoretic patterns of transferrin, and (2) to survey the gene constitution of transferrin in a commercial population of the domestic quail.
Sera were added with iron, heated for 5 min at 65°C (Stratil, 1967), then were investigated by means of horizontal starch gel electrophoresis. Hydrolysed starch from Connaught Medical Laboratories, Toronto, was used. A discontinuous citrate/Tris/LiOH/borate buffer system (pH 8.0) of Ferguson & Wallace (1961) was employed. The gels were stained with Amido Black 10B.     

Linkage between the loci for serum albumin and vitamin D binding protein (GC) in the Japanese quail

Vitamin D binding protein ( GC ) and serum protease inhibitor ( PI ) have been added to genetic markers in the Japanese quail. Both loci were controlled by autosomal codominant alleles named GC^A, GC^B and PI^A, PI^B, PI^C, respectively. Close linkage between the loci for serum albumin ( ALB ) and GC protein is reported. Two recombinants were observed in 145 informative offspring of 14 families. The recombination frequency between the loci was estimated as 0.014±0.006. Thus, GC was assigned to linkage group II in the Japanese quail. No signs of linkage were observed among the loci for the ALB-GC complex, PI. serum prealbumin 2 ( PA2 ), phosphoglucose isomerase ( PG1 ), 6-phosphogluconate dehydrogenase ( PGD ) and esterase-D ( ESD ).     

The growth and mortality of larval herring, Clupea harengus L., in the River Blackwater Estuary, 1978–1980

Herring larvae were sampled in the Outer Thames Estuary and the River Blackwater Estuary in the springs of 1978, 1979 and 1980. Data were collected on larval stage, yolk sac and post yolk sac, larval length and total larval numbers. Newly hatched larvae were 6.8±0.5 mm long and the growth rate of yolk sac larvae was estimated at 0.18 mm d⁻¹ ( L = 6.8±0.186 t ). The growth rate of post yolk sac larvae increased to 0.43mm d⁻¹ ( L = 11±48.0±43 t ). Mortality estimates, derived from total numbers in the summed estuary segments, varied between the years and the cohorts within the year. In 1979 the mortality rates were 0.061 d⁻¹ and 0.074 d⁻¹ for the two cohorts. The mean size of the larval population was estimated at 2.48×10⁹ (1.63–3.77 × 10⁹) which agreed well with population size estimates from egg laying and from catch in numbers at age together with estimated fishing mortality rates.     

Genetic variation of pancreatic esterase isozyme in Japanese quail

A genetic variation was found in pancreatic esterases of Japanese quail which appeared to be arylesterase. It was found on the cathode side in the agar gel electrophoresis. Three phenotypes, A, B and AB, were observed. These phenotypes were shown to be controlled by one autosomal locus, designated as Es-4 , with co-dominant alleles Es-4^A and Es-4^B.
Es-4 esterase isozymes were detected in all the individuals from about 4 days of age, but the activity was very weak. However, it gradually increased to reach a level almost the same as that of a mature quail from about 15 days of age.     

Uptake and distribution of cadmium in the egg of the teleost, Oryzias latipes

Eggs of Oryzius latipes in the blastula stage were exposed to M/100 artificial sea water which contained cadmium at the concentrations of 0.1, 1.0, 10.0, 20.0 or 50.0 mg 1⁻¹. The 96 h TL₅₀, value for cadmium was estimated to be 20 5 mg 1⁻¹. When the eggs were incubated for 24 h in the M/100 sea water with 10.0 mg Cd 1⁻¹ and then rinsed in glycine buffer solution (pH; 2.0), the cadmium content of the egg decreased markedly. Cadmium levels were determined in parts of the embryonic body, the chorion and the yolk sac. The most cadmium was detected in the chorion (94.6%). Prolonged cadmium exposure revealed that most of the cadmium was absorbed by the chorion and little was detected in the embryonic body and the yolk sac.     

Oxygen uptake in developing eggs and larvae of the cod, Gadus morhua L.

Unfertilised cod eggs showed a mean oxygen uptake rate at 5°C of 0.089 μl O₂, dry wt.⁻¹ h⁻¹; this gradually rose to 0.768 μl O₂ mg dry wt.⁻¹ h⁻¹ in eggs about to hatch. From hatching to complete yolk absorption larvae respired at 1.6 μl O₂, mg dry wt.⁻¹ h⁻¹. During starvation following yolk absorption, uptake fell significantly to 1.1 μl O₂, mg dry ⁻¹ h⁻¹. Much of this decrease in oxygen consumption was shown to be caused by reduction in activity. Loss of weight during the embryo and larval phases could not easily be reconciled with total oxygen consumption; it is suggested that cod embryos and larvae may not rely solely upon endogenous energy reserves during development.     

Ascorbic acid and α-tocopherol levels in larvae of Atlantic halibut before and after exogenous feeding

Ascorbic acid (AA) and α-tocopherol (α-TOH) levels in whole Atlantic halibut larvae were constant during the yolk sac stage at 170 and 131 ng individual⁻¹, respectively. At hatching c . 80% of the AA and 97% of the α-TOH were contained within the yolk-sac compartment. With development, AA and α-TOH levels in the yolk decreased, at different rates. At first feeding (at 200 day degrees post hatch, D°PH)>95% of AA but <30% of α-TOH in the yolk at hatching had been transferred to the larval body. Transfer of α-TOH was completed at 360 D°PH, when the yolk was completely absorbed. The plankton offered to the larvae at first feeding (chiefly Temora longicornis ) contained 756 μg g⁻¹ AA and 120 μg g⁻¹α-TOH (dry weight). The AA content increased to 472 ng individual⁻¹ within one week after first feeding, while it declined slightly in unfed larvae. In fed larvae the AA content reached c . 3500 ng individual⁻¹ at 580 D)PH. The α-TOH content increased only slightly in the first week of feeding (206 to 431 D°PH), but then increased to > 800 ng individual⁻¹ at 483 D°PH.     

Changes in ion content and transport during development of embryonic rainbow trout

Wet mass and water content of four lots of whole eggs did not change throughout embryonic development of rainbow trout Oncorhynchus mykiss. Eggs in all four lots accumulated Na⁺. Eggs in lots 2 and 4 also accumulated Ca²⁺ and Cl^-, whereas eggs in lot 1 showed no significant change in Ca²⁺ or Cl^- and eggs in lot 3 showed no change in Cl^-and a small loss of Ca²⁺. Although the Na⁺ content of embryonic tissues increases in the later stages of development, the yolk sac content remained constant, indicating uptake of Na⁺ from the environment. Na+ uptake by whole eggs was non-saturable, consistent with diffusion of Na⁺ across the chorion into the perivitelline fluid. Na⁺ uptake in dechorionated embryos was saturable, as was Ca²⁺ uptake by both whole eggs and dechorionated embryos, consistent with active uptake or facilitated diffusion mechanisms at the surface of embryos. Very low Ca²⁺ uptake rates in dechorionated embryos suggest that the Ca²⁺ uptake mechanism is not fully developed until after hatching.     

Effect of high-temperature, short-time (HTST) pasteurization on milk containing low numbers of Mycobacterium paratuberculosis

The efficacy of high-temperature, short-time (HTST) pasteurization (72 °C/15 s) when low numbers (≤ 10³ cfu ml ⁻¹ ) of Mycobacterium paratuberculosis are present in milk was investigated. Raw cows' milk spiked with Myco. paratuberculosis (10³ cfu ml⁻¹, 10² cfu ml⁻¹, 10 cfu ml⁻¹, and 10 cfu 50 ml⁻¹) was subjected to HTST pasteurization using laboratory pasteurizing units. Ten bovine strains of Myco. paratuberculosis were tested in triplicate. Culture in BACTEC Middlebrook 12B radiometric medium detected acid-fast survivors in 14·8% and 10% of HTST-pasteurized milk samples at the 10³ and 10² cfu ml⁻¹ inoculum levels, respectively, whereas conventional culture on Herrold's egg yolk medium containing mycobactin J detected acid-fast survivors in only 3·7% and 6·7% of the same milk samples. IS900-based PCR confirmed that these acid-fast survivors were Myco. paratuberculosis . No viable Myco. paratuberculosis were isolated from HTST-pasteurized milk initially containing either 10 cfu ml⁻¹ or 10 cfu 50 ml⁻¹.     

Protective effect of modified glucomannans against aurofusarin-induced changes in quail egg and embryo

The aim of this study was to evaluate effects of modified glucomannans (Mycosorb) on egg yolk and liver of the day-old quail after aurofusarin inclusion in the maternal diet. Fifty-four 45-day-old Japanese quail were divided into three groups and were fed ad libitum a corn-soya diet balanced in all nutrients. The diet of the experimental quail was supplemented with aurofusarin at the level of 26.4 mg/kg feed in the form of Fusarium graminearum culture enriched with aurofusarin or with aurofusarin plus Mycosorb at 1 g/kg feed. Eggs obtained after 8 weeks of feeding were analysed and incubated in standard conditions of 37.5 degrees C/55% RH. Samples of quail liver were collected from day-old hatchlings. Main polyunsaturated fatty acids (PUFAs) of the egg yolk were analysed by gas chromatography, and tocopherols and tocotrienols were analysed by HPLC-based methods. Inclusion of aurofusarin in the maternal diet was associated with decreased proportions of docosahexaenoic acid and increased proportions of linoleic acid in major lipid fractions of the egg yolk as well as with decreased concentrations of alpha- and gamma-tocopherols, alpha- and gamma-tocotrienols in egg yolk and liver of a day-old quail. Inclusion of modified glucomannans (Mycosorb) into the quail diet simultaneously with aurofusarin showed a significant protective effect against changes in PUFA and antioxidant composition in the egg yolk and liver of quail. It is suggested that a combination of mycotoxin adsorbents and natural antioxidants could be the next step in counteracting mycotoxins in animal feed.     

Quail Egg Yolk: A Novel Cryoprotectant for the Freeze Preservation of Poitou Jackass Sperm

For many years, attempts have been made to establish a sperm bank for the Poitou jackass population which is threatened with extinction. Unfortunately, no cryopreservation technique has ever been described for spermatozoa of this species. In an attempt to find a suitable technique, we studied the relative effectiveness of chicken egg yolk and quail egg yolk in preserving the motility and characteristics of movement of Poitou jackass spermatozoa during the freezing–thawing process. Semen was diluted to 60 × 10⁶sperm/ml in a preservation medium containing 4% (v/v) glycerol with 0, 2, 5, 10, 15, or 20% (v/v) of chicken or quail egg yolk. The chemical composition of these two eggs was compared. Effects were assessed using an automated analyzer which measured curvilinear velocity (VCL), straight line velocity (VSL), and the velocity of the average path. Linearity was defined as VSL/VCL × 100. The amplitude of the lateral head displacement was also measured. It was found that after the freeze–thaw process, quail egg yolk improved the percentages of motile and progressively undulating spermatozoa and the movement characteristics compared with chicken egg yolk. The optimal concentration of quail egg yolk was 10%. The general composition of the two types of egg yolk were similar, but quail egg yolk contained significantly more phosphatidylcholine, less phosphatidylethanolamine, and a smaller ratio of polyunsaturated to saturated fatty acids than chicken egg yolk. The improvement of motility for frozen–thawed Poitou jackass spermatozoa using frozen–thawed quail egg yolk compared to chicken egg yolk may be due to the differences in composition of the two yolks.     

Physiological mechanisms of buoyancy in eggs from brackish water cod

Newly fertilized eggs of brackish water (Gotland, Baltic Sea) and marine (Lofoten, Norway) cod were investigated with regard to specific gravity, wet and dry weight, water content, chorion weight, and content of protein, free amino acids (FAA), and ions. The eggs had neutral buoyancies equivalent to a salinity of 14^.3% (range 11^.5–16^.2%) in brackish water, and 33^.0% (range 31^.8–34^.5%) in the marine environment. A buoyancy model was developed and showed that this difference was mainly caused by differences in egg water content which was 96.6 ± 0^.47% and 92.7 ± 0.45% in the brackish and marine eggs, respectively. The higher water content of the brackish eggs resulted from increased water uptake during final oocyte maturation due to higher intracellular contents of FAA, Cl ^– and NH₄⁺. SDS polyacrylamide gel electrophoresis of eggs and oocytes, and measurements of egg protein content suggested that the FAA pool of both egg types originated from hydrolysis of specific yolk proteins. The main contributor seemed to be a protein with a molecular weight of 100 kDa.     

Effects of egg composition and prey density on the larval growth and survival of lake whitefish (Coregonus clupeaformis Mitchill)

Eggs were collected from two stocks of lake whitefish, Coregonus clupeaformis , in Lakes Michigan and Huron to assess the effect of egg composition and prey density on larval growth and survival. Egg composition parameters including wet weight (mg egg⁻¹), dry weight (mg egg⁻¹), percent water, total caloric content (cal egg⁻¹), caloric density (cal egg⁻¹), percent lipid content, and total lipidcontent (mg egg⁻¹) were measured. Fish hatched from six parental females in each stock were fed one of four rations (0, 18, 24, 50 brine shrimp larva⁻¹ day⁻¹) after yolk sac absorption. Length at hatch, endogenous growth, exogenous growth, and survival were measured during a 42-day laboratory experiment. Length at hatch of larvae was positively related to egg caloric content ( r ²=0.780). Endogenous growth for lake whitefish larvae was positively related to percent lipid content ( r ²=0.896) and total egg lipid content ( r ²=0.876) of parental females. Exogenous growth and survival of larval lake whitefish was positively related to prey availability. Larval fish growth was accurately modelled ( r ²=0.973) as a function of prey abundance using a threshold-corrected hyperbolic equation. These results indicate that both egg composition and prey availability have the potential to influence the growth and survival dynamics of larval lake whitefish significantly.     

Energy metabolism in eggs and larvae of the Senegal sole

Oxygen consumption in Solea senegalensis increased during the egg stage reaching values close to 4 nmol O₂ ind⁻¹ at hatching. After hatching, larval oxygen consumption continued to increase, reaching a maximum rate of 9.97⁻¹±87 nmol O₂ ind⁻¹ h⁻¹ 2 days after the opening of the mouth. Body nitrogen content decreased mainly after exhaustion of yolk reserves. Carbon content decreased during the whole endogenous feeding phase, although it decreased twice as quickly after yolk-sac absorption. The free amino acid (FAA) depletion rate was higher during egg development and the yolk-sac period. Complete yolk absorption coincided with the consumption of the 90% of initial FAA content in the eggs and the remaining FAA were consumed at a lower rate. Based on stoichiometrical calculations, FAA appears to be the most important energy substrate during the egg stage (86%) in the Senegal sole. During the period from hatching to the mouth opening, contributions of FAA and lipids as metabolic fuels were similar (41 and 47%, respectively). The decrease in larval protein content during starvation indicates that amino acids from body protein are used as energy substrates under food deprivation.     

Evaluation of the chick embryo for the determination of relative virulence of Neisseria meningitidis

Abstract The chick embryo model was evaluated as a method to compare virulence between selected strains of Neisseria meningitidis . Inoculation of 13-day-chick embryos via the egg yolk distinguished strains having an LD₅₀ of 10³ colony forming units (CFU) or greater (low virulence) from those having an LD₅₀ of approximately 10¹ or less (high virulence). A strain of serogroup B and a spontaneous nonpiliated strain of group C were found to be of relatively high virulence while a strain of N. lactamica , a serogroup A carrier strain, and certain nongroupable strains were found to be of low virulence. Strains having an LD₅₀ of 10² were not differentiated from either of these. Alternatively, inoculation of the chorioallantoic membrane (CAM) of 9-day-old chick embryos statistically differentiated most strains of N. meningitidis although inoculation via this route was less sensitive.     

Oxygen consumption in Oreochromis niloticus (L.) in relation to development, salinity, temperature and time of day

Oxygen consumption of Oreochromis niloticus at different stages of development was studied in relation to salinity, temperature and time of day, using a Warburg apparatus. The oxygen consumption of newly hatched (0–14 h) larvae was 3.40 μl O₂ larva⁻¹ h⁻¹, of older yolk sac larvae 10.09 μl O₂ larva⁻¹ h⁻¹, and of one-month-old fry 32.99 μl O₂ larva⁻¹ h⁻¹. The QO₂ values showed a decrease with development and growth, ranging from 21.2–26.0 μl O₂ mg⁻¹ h⁻¹ in newly hatched larvae to 2.97 μl mg⁻¹ h⁻¹ in one-month-old fry. Changes in oxygen consumption occurred with salinity, the highest being at 17%o. Active larvae (12-24 mm T.L.) showed a doubling of consumption with a 10° C rise in temperature, and their Q₁₀ factor increased from 2.25 to 3.43 with increasing size. Day-old yolk-sac larvae, late yolk-sac larvae (5 days old) and fry of 12 14 mm length all showed a depression in oxygen consumption at midnight followed by a dawn rise.     

Ovarian structure and batch fecundity in Lophiomus setigerus

The ovarian structure and batch fecundity of anglerfish Lophiomus setigerus were examined from specimens collected in the East China Sea during March 1991 to September 1995. The right and left ovarian lobes were connected at their posterior ends. Stalk-like ovigerous lamellae protruded from the ovarian wall. During the spawning season, gelatinous material was secreted from the epithelia of both the ovigerous lamellae and ovarian wall, and these epithelia showed morphological changes accompanying the ovarian maturation cycle. Tertiary yolk, migratory nucleus, and mature stage oocytes occurred in the ovaries between May and November, when females with postovulatory follicles and developing vitellogenic oocytes were collected also. These results suggested an extended spawning season during which females undergo repeated spawnings. When the most advanced oocytes attained the secondary yolk stage, they formed a batch that separated from the adjacent group of smaller oocytes. Batch fecundity ( F ) in 20 females with secondary yolk stage ovaries was related to total length (L_T, mm) as F= 556.2 L_T^1.157 (300≤L_T≤396).