Egg Diameter Research Articles

Reproductive Biology of African River Prawn (Macrobrachium Vollenhovenii: Herklots 1857) in the Interconnecting Lagoons of South-Western Nigeria

Reproductive biology is important in the life of organisms, because through it, ripe and fecund females produces their young. Macrobrachium vollenhovenii is one of the species of Macrobrachium found in fresh and brackish waters of West Africa. It is one of the largest species of Macrobrachium known which makes it a suitable choice for aquaculture in Nigeria. The sex ratio, fecundity, egg diameter and the gonado-somatic index of M. vollenhovenii from Badagry, Lagos and Epe Lagoons, Nigeria were investigated. The samples were collected monthly from the lagoons for 24 months between June, 2013 and May, 2015. The sex ratio showed that there was significant difference (P 0.5). The egg diameter from the three lagoons ranged from 465 – 780 µm while the Gonado-Somatic Index (GSI) from the three lagoons ranged from 0.78 – 14.29 %. In this study, it was observed that males of M. vollenhovenii occurred more in Badagry and Epe Lagoons, which might be due to the freshness of the environment while females were predominated in Lagos Lagoon, due to their search for a spawning ground especially when the salinity of the water is high. This study would therefore, serve as a basis upon which further researches on the reproductive biology of M. vollenhovenii could be based.

Effect of a newly synthesized quinoline-based compound (PPQ-8) on murine schistosomiasis mansoni.

Schistosomiasis represents a public health problem and praziquantel is the only drug used for treatment of all forms of the disease. Thus, the development of new anti-schistosomal agents is of utmost importance to increase the effectiveness, reduce side effects and delay the emergence of resistance. The present study was conducted to report the therapeutic efficacy of PPQ-8, a new synthetic quinoline-based compound against Schistosoma mansoni. Mice were treated with PPQ-8 at day 49 post infection using two treatment regimens (20 and 40 mg/kg). Significant reductions were recorded in hepatic (62.9% and 83.6%) and intestinal tissue egg load (57.4% and 73.5%), granuloma count (75.4% and 89.1%) and diameter (26.2% and 47.3%), in response to the drug regimens, respectively. In addition, both treatment regimens induced significant decrease in liver (23.3% and 32.8%) and spleen (37.5% and 45.3%) indices. Also, there were significant reductions in mature ova, total worm and female count, which were more prominent with the higher dose. The reduction in the level of nitric oxide in the liver by both therapeutic regimens to 22.5% and 47.2% indicates the anti-oxidant activity of PPQ-8. Bright field microscopic examination of worms recovered from infected and PPQ-8-treated mice showed nearly empty intestinal caeca with no observable changes in the tegument. Our findings hold promise for the development of a novel anti-schistosomal drug using PPQ-8, but further in vitro and in vivo studies are needed to elucidate the possible mechanism/s of action and to study the effect of PPQ-8 on other human schistosomes.

ВЕТЕРИНАРНО-ГИГИЕНИЧЕСКАЯ ОЦЕНКА КАЧЕСТВА КУРИНЫХ ЯИЦ ПРИ ИСПОЛЬЗОВАНИИ КОРМОВОЙ ДОБАВКИ «ПРИНАРОВCКАЯ»

The aim of the studies was to conduct a veterinary-hygienic assessment of changes in the eggs productivity of laying hens, after the use of the “Prinarovskaya supplement of fish (DKR)” in their main diet, which is a homogeneous dry mass made from chilled river fish, by-products of fish processings, as well as grain products (wheat bran). The method of production of the additive in-cludes the following steps: grinding, cavita-tion heating and subsequent drying of the resulting mixture. The studied supplement contains a number of amino acids, vitamins and minerals, etc. The object of the study were laying hens of the LomannLsn-Classic breed at the age of 131 days. “Prinarovskaya DKR” were introduced into the diet of ex-perimental laying hens: of the 1st experi-mental group 8 g of “Prinarovskaya DKR” were introduced per 100 g of the main ration (RR); The 2nd experimental group - 6 g. DKR to main ration; 3rd experimental group - 4 g. DKR to main ration; the control group was fed only main ration - feed PK1-1G_1227 (GOST: R 51851-2001). A veteri-nary-hygienic assessment of the quality of eggs, obtained from laying hens, when feed-ing a new feed additive “Prinarovskaya” was carried out. We kept daily records of laid eggs by groups, the period of the beginning of oviposition. The egg production were calculated of the initial and middle laying hens , the egg production intensity for 120 days. To assess egg productivity, the weight of laid eggs, the egg mass for a certain peri-od of egg laying, and the feed costs per 10 laid eggs were determined. Organoleptic, physical, and chemical methods were used to evaluate egg quality. Egg mass is an important indicator of egg nutrition. GOST 31654-2012 "Food eggs. Technical conditions ”, as well as the requirements for chicken hatching eggs, the minimum weight of food and hatching eggs (45 g) is indicated, below which the imple-mentation and incubation of eggs is not rec-ommended [1]. In studies, the following indicators were taken into account: large and small diameter of eggs, egg density, egg shape index of laying hens of different groups. To assess the state of the internal contents of the egg after opening, the follow-ing indicators were taken into account: pro-tein mass, yolk mass, shell mass, egg vol-ume. An external examination of the eggs as-sessed the condition of the shell, the pres-ence of cracks, growths and depressions. The study indicates a positive effect of the feed additive "Prinarovskaya" on the egg produc-tivity of birds in all periods of egg laying

Fecundity estimation of Indian Potasi, Neotropius atherinoides in Bangladesh

Fecundity estimation has obvious significance in aquaculture, since the size of brood stock, amount of rearing facilities and necessity of other equipment’s are dependent on fecundity. The study has been conducted on fecundity estimation of Indian potasi, Neotropius atherinoides, based on 202 females collected from the Kangsha River flowing through Netrokona district during the period from January to June 2013. The standard length (SL) range of female were 47-66, 50-64, 57-68, 50-66, 56-66 and 60-76 mm and range of body weight were 1.07-3.56, 1.23-3.35, 2.36-3.81, 1.69-4.31, 2.33-5.59 and 3.18-5.14 g in January, February, March, April, May and June, respectively. The mean Gonado somatic indices (GSI) were very low from January to March but these were abruptly high during subsequent three months. Based on mean GSI the spawning season of this species was assumed from April to June over the study period. Scatter plot of standard length with corresponding GSI revealed that the minimum length of mature female was 50 mm SL. Egg diameter frequency distribution of a mature ovary showed almost only one major mode of egg size suggested that the fish is a single spawner, and summation of eggs in that mode was regarded as the fecundity of a female Indian potasi. The regression equation of the relationship between standard length and fecundity was as, Fecundity = 0.0017 SL 3.55. The relative fecundity and the absolute fecundity of a fish having SL of 62 mm was 1477 per g and 3921, respectively based on F-SL relationship. The relationship between body weight and fecundity was as, Fecundity = 1371.3 BW-650.8. The absolute fecundity of a fish having BW of 3.51 g was 4162 respectively based F-BW relationship. The relationship between ovary weight and fecundity was as, Fecundity = 6244.3 OW + 967.52. The absolute fecundity of a fish having ovary weight of 3.51 g was 7211 based F-OW relationship. The correlation coefficient of all above analyses were very high (>0.755) attributing that standard length, body weight and gonad weight were highly positively correlated with fecundity of Indian Potasi, Neotropius atherinoides.
 Res. Agric., Livest. Fish.6(3): 421-429, December 2019

Egg size and density estimates for three gadoids in Icelandic waters and their implications for the vertical distribution of eggs along a stratified water column

Abstract The vertical distribution of fish eggs can have important consequences for recruitment through its influence on dispersal trajectories and thus connectivity between spawning and nursery locations. Egg density and size are key parameters for the modelling of vertical egg distributions, both of which show variation at the species level, as well as between and within individuals (i.e., through ontogeny). We conducted laboratory experiments on the eggs of wild-spawning cod, haddock and saithe from Icelandic waters to estimate these parameters throughout ontogeny. Subsequently, this information was used in a 1-dimensional model to generate vertical distributions for each species along a stratified water column. Saithe eggs were significantly smaller and less dense than cod and haddock eggs. Cod eggs were slightly denser than haddock eggs in the first ontogenetic stage but statistically similar in the later stages. No significant differences were found between the egg diameters of cod and haddock. For each species, both parameters changed significantly through ontogeny. Yet despite these significant results, the 1-d model suggests that neither the interspecific nor ontogenetic differences would have a significant impact on the vertical egg distributions. Only under highly stratified conditions, when buoyancy is minimised due to the freshwater layer, do distributional differences become evident. In such situations, incorporating intraspecific variation in egg density into the model substantially reduced the distributional differences and this is highlighted as an important consideration for the modelling of pelagic vertical egg distributions.

Changes in the composition and abundance of ichthyoplankton along environmental gradients of the southern Baltic Sea

AbstractThe research focuses mainly on the ichthyoplankton of the Baltic deeps – the inflow route from the North Sea. The ichthyoplankton was represented by eggs and larvae of nine fish species: sprat, cod, herring, European flounder, fourbeard rockling, longspined bullhead, straightnose pipefish, sand goby and great sandeel. The species composition of ichthyoplankton varied depending on the location of a given site – the number of taxa ranged from one to five. The Slupsk Furrow was the most diversified area in terms of the number of taxa, while the highest abundance of ichthyoplankton occurred in the Bornholm Basin. The sprat clearly dominated and inhabited all the surveyed depths. Of the remaining species, only cod eggs as well as eggs and larvae of the fourbeard rockling significantly contributed to this formation. They occurred within their main spawning grounds (Bornholm Deep in the near-bottom layers) and secondary spawning grounds (Slupsk Furrow and Gdansk Deep) where salinity and oxygenation of water favored their development. Biometric research has shown that the diameter of eggs was within the size range typical of the Baltic Sea.

Biological Parameters of Blacksaddled Coralgrouper (Plectropomus laevis Lacepède, 1801) Eggs and Larvae

Blacksaddled coralgrouper, Plectropomus laevis, is an endangered species of marine fish. As part of conserving their existence in the wild, culture of this species has been started. However, knowledge of biological parameters of this species as important indicators to observe the fish growth in mariculture scale, is limited. The purpose of this study was to observe biological parameters during eggs, larval to juvenile stage of blacksaddled coralgrouper in mariculture hatchery. The eggs were obtained from natural spawning of domesticated broodstocks. Larvae rearing was done in hatchery at three different times as replicates. Larval were fed with zooplankton which consist of rotifers Brachionus sp., wild copepods and Artemia. Artificial feed was also given to the fish larvae. Larval samples were taken one Day After Hatching (DAH), then continued every 5 days started at 5 to 45 DAH by using five larvae each sampling time. The observed parameters were diameter of eggs and oil globule, total length and standard length of larvae length of dorsal and pelvic fin spines of larvae. Furthermore, growth pattern of those length parameters was analysed by regression equation. The result showed that diameter of blacksaddled coralgrouper eggs was 835.19±15.29 µm, while oil globule was 177.78±10.30 µm. The growth patterns of larval total length and standard length were exponential, while dorsal and pelvic fin spines were polynomial. The length of time from larvae to achieve juvenile stage was range between 45-50 days. All of these information can be used as references either in larvae rearing or for further study of the fish.

Age determination, growth indices and reproduction biology of Prussian carp, Carassius gibelio (Bloch, 1782) from four reservoirs in Golestan Province, Southeast Caspian Sea

This study aimed to determine age and growth indices of Prussian carp, Carassius gibelio collected a total of 942 specimens on a monthly basis from February through September 2015 in three dam lakes including Golestan, Boostan and Voshmgir and one reservoir named Alakoli from the Southeast Caspian Sea. The largest specimen was a female with 220 mm in total length (TL) and 139.787 g in weight from Voshmgir. The maximum condition factor of the fish increased markedly during late April- August in all areas. Growth pattern was positive allometric in females from Alakoli, while negative allometric in females from Golestan, Boostan and Voshmgir and also in males from Voshmgir. The isometric growth observed in males from Golestan and Boostan as well as from Alakoli. The growth parameters of von Bertalanffy fit to the mean observed total lengths-at-age for each sex separately were estimated as L∞= 378.09 mm, K= 0.12, t0= -0.35 for females, L∞= 309.38 mm, K= 0.17, t0= -0.02 for males, and as L∞= 355.74 mm, K= 0.13, t0= -0.35 for total population in Golestan; L∞= 299.06 mm, K= 0.18, t0= -0.10 for females, L∞= 574.17 mm, K= 0.07, t0= -1.04 for males, and as L∞= 338.43 mm, K= 0.15, t0= -0.34 for total population in Boostan; L∞= 296.37 mm, K= 0.20, t0= -0.20 for females, L∞= 186.23 mm, K= 0.51, t0= -0.42 for males, and as L∞= 302.94 mm, K= 0.19, t0= -0.18 for total population in Voshmgir; and L∞= 347.99 mm, K= 0.04, t0= -0.12 for females, L∞= 530.92 mm, K= 0.01, t0= -0.18 for males, and as L∞= 477.73 mm, K= 0.01, t0= -0.40 for total population in Alakoli. A prolonged spawning period was observed from April through August. Maximum egg diameter and absolute fecundity were 1.39 mm and 72865 oocytes in population inhabiting Voshmgir respectively.

Identification of Magelang Ducks to Analyze Morphological Diversity in Ngadirojo Village, Secang District, Magelang Regency

Magelang duck is one of the productive local poultry producing meat and eggs. This study aims to compare the production and quality of eggs between local ducks at duck breeding centers in Ngadirojo Village, Secang District, Magelang Regency. The material used was 11 samples of ducks and eggs from different breeders. Based on the results of the study it was found that the average morphological measurements in ducks are bodyweight of 1.94 kg, body length 30.67 cm, neck length 14.18 cm, chest circumference 39.09 cm, and body temperature 40.18 cm. The average quality of Magelang duck eggs is egg weight of 64.46 gr, egg index 1.24 cm, eggshell thickness 0.06 cm, egg length 5.63 cm, and egg diameter 4.54 cm. The average albumen weight was 26.47 gr, yolk weight 23.69 gr, albumen width 8.87 cm, yolk width 4.49 cm, albumen height 0.77 cm, and yolk height 2.00 cm. The morphology of duck size will greatly affect egg production. The weight of female and male ducks is almost the same, ranging from 1.5-2 kg. Magelang duck egg production is about one grain every day. Each egg production will be different. This can be influenced by several factors including the quality of the seeds and the feed system that is given. Standard normal egg weight ranges from 65-70 grams. In maintenance, every 10 female ducks will be added by 1 male duck. Keywords: Identification, Morphology, Magelang Duck, Ngadiroj

Preliminary Study Rearing of Oryzias sp. from Tunda Island, Indonesia, Under Laboratory Condition

Oryzias sp. from Tunda Island, Indonesia has the potential as a model organism in laboratories and also ornamental fish. Basic information regarding maintenance during adaptation post-transportation from its habitat in nature, embryo incubation and maintenance of larvae is needed as a basis for breeding activities. The results showed that Oryzias sp. from Tunda Island can adapt, spawning and produce a total 262 eggs (diameter 0.88-1.02 mm) in a controlled environment. Eggs from spawning in nature begin to hatch on the 11th incubation day, the hatching peak occurs on the 13th day with a hatching process 4-9 days at 25-27oC. The hatching rate ranges from 57.14-100% and the survival of 5 days old lavae after hatching is 72.72-100.00%. The transportation technique in this study has not been able to suppress fish mortality during post-transportation rearing.
 

Induction of gonadal maturation in mahseer fish (Tor douronensis) using the PMSG hormone, antidopamin

Spawning of pedih fish (Tor douronensis) is seasonal that occur twice a year. This causes limitation of mature broodstock. Therefore, the study was done to examine the effect of PMSG + antidopamin hormone in accelerating gonadal maturity female broodstock of pedih fish (Tor douronensis) at different concentration. This research used Completely Randomized Design (CRD) method, using 12 test fish with 4 treatments, namely treatment A (0 mL/kg fish), B (0.5 mL/kg fish), C (1 mL/kg fish), D (1.5 mL/kg fish). The ANOVA test results showed that induction of gonadal maturation in pedih fish (Tor douronensis) using different concentration of PMSG + AD had a significant effect on broodstock weight gain (W), egg diameter (mm) and relative egg diameter (%/day) (P <0.05). The study indicated that the treatment C (1 mL/kg of fish) produced the highest value on the broodstock weight gain (0.17 kg), egg diameter (1.68 mm), relative egg diameter (8,03%/day).

Effect of PMSG+AD hormone variation on the gonadal maturation of Pedih fish (Tor douronensis)

Pedih (Tor douronensis) is a freshwater fish that live in mountainous areas and swift rivers in the interior of Aceh. The aimed of this research was to analyze the dosage of PMSG+AD hormone orally for the gonadal maturation of pedih (Tor dauronensis). This research was conducted at technical implementation unit of fish breeding center Lukup Badak, Pegasing district, Aceh Tengah on Febuary to March 2018. The method used was Completely Randomized Design (CRD) with 4 level of treatment and three replications: 0 ml/kg feed, 0.3 ml/kg feed, 0.5 ml/kg feed and 0.7 ml/kg feed. The result of ANOVA test showed that different dosage of PMSG+AD hormone orally showed significant effect on the weight of broodstock, relative weight, gonad maturations index, eggs diameter, and relative eggs diameter. The result of Duncan test showed that the best dosage was found 0.7 ml/kg feed, but this treatment was not significantly different with the dosage of 0.5 ml/kg feed.

Growth pattern, reproduction and food habit of palau fish Osteochilus vittatus in Batanghari River, Jambi Province, Indonesia

Batanghari River is one of the fishing locations in Jambi Province, Indonesia. One of the commercial freshwater fish in this river is silver shark minnow Osteochilus vittatus. Presently, there was no study on the bioecology of this species in Batanghari river. Therefore, the aims of this research were to analyze the growth pattern, reproduction, and food habits of silver shark minnow in Batanghari River, Indonesia. Data were collected in February, April, June, September, and October 2018. The samples were preserved with alcohol 70%. The length-weight relationships were analyzed using the linear allometric model, gonad maturity was observed by morphologically, and fecundity was calculated by the gravimetric method. The results showed that this fish had an isometric growth pattern. The fish fed on phytoplankton and indicated as herbivorous plankton feeder. Bacillariophyceae and Chlorophyceae were predominant food items. The fish spawn around the year partially with fecundity between 2,726 - 19,202 eggs. The gonad maturity index ranges from 5.38% to 11.44%, and the egg diameter ranged from 0.40 to 1.27 mm.

THE STIMULATION OF GONAD MATURITY OF ASIAN REDTAIL CATFISH Hemibagrus nemurus (Valenciennes, 1840) THROUGH INDUCTION OF OOCYTE DEVELOPER (Oodev) HORMONE

Oodev hormone application has been applied to stimulate gonadal maturity so that fish fry could be available outside the spawning season. This research aimed to study the effect of Oodev hormone on the gonadal maturity of asian redtail catfish Hemibagrus nemurus (Valenciennes, 1840). This research method used a completely randomized design (CRD) with 4 doses treatments, i.e 0, 0,25, 0,50, 1,00 ml/kg. A total of 8 fish were used as replications for each treatment. The parameters measured were the gonado somatic index (GSI) and egg diameter. The results showed that the effect of Oodev hormone on GSI and egg diameter was significantly different (P&lt;0.05). A higher Oodev hormone dose caused an increase of GSI and egg diameter size. The recommended Oodev dose for application is 1 ml/kg.

Fluctuating asymmetry, parasitism and reproductive fitness in two species of gammarid crustacean.

Fluctuating asymmetry (FA), defined as random deviations from perfect bilateral symmetry, is assumed to reflect developmental instability. FA is predicted to increase in response to environmental stress, including parasite infection. In addition, based on theory we predict a higher FA in sexually selected traits, due to their greater sensitivity to stress. We investigated the relationships between FA, parasitism and reproductive fitness in 2 species of gammarid crustacean, incorporating both sexual and non-sexual traits. We tested the hypothesis that gammarids infected by vertically transmitted Microsporidia will display higher levels of FA than those infected by horizontally transmitted trematodes, because vertically transmitted Microsporidia can be present at the earliest stages of host development. We found little evidence for a relationship between FA and fecundity in Gammarus spp.; however, egg diameter for infected female Gammarus duebeni was significantly smaller than uninfected female G. duebeni. FA was not correlated with brood size in females or with sperm number in males. In contrast to our prediction, we report a lower relative FA in response to sexual traits than non-sexual traits. However, FA in sexual traits was found to be higher in males than females, supporting the theory that sexual selection leads to increased FA. Additionally, we report a negative correlation between FA and both trematode (Podocotyle atomon) and PCR-positive microsporidian (Nosema granulosis and Dictyocoela duebenum) infections and interpret these results in the context of the parasites' transmission strategies. FA in G. duebeni and G. zaddachi appears to associate with trematode and microsporidian presence, although reproductive fitness is less altered by infection.

Life history and other biological traits of Capoeta buhsei (Kessler,1877) in the Gharachay River, Saveh

Abstract: Capoeta buhsei is endemic to the Namak lake and littlee is known of its life history in Iranian waters. Life history characteristics we examined in 92 specimens collected from the Gharachay River. In july and January of 2011 and October of 2012. Sampling was by Electroshoker.Observed maximum age was +4 years in female. Sex Ratio (male: female) was 1:0/73, and length –weight relationships were BW=35/55.TL 32 in male and BW=14/8TL-30/7 in female. Mean egg diameter (ED) was 0/8726 0/12mm ranging from 0/67 to 1/1 mm. Mean absolute (AF)and relative. Fecundity (RF) were 4917/2157 ( 1690/04 SE) egg/female and 69/1( 16/15SE) eggs.g-1 body weight, respectively. AF and ED were found to increase significantly with increasing fish size, wherease RF increased significantly with both fish TL and weight.

Effect of different protein levels on reproductive performance of snakehead murrel Channa striatus (Bloch 1793)

In this study the effect of different protein levels on reproductive performance of C.striatus was conducted. Snakehead juveniles (65.5 ± 0.2 g) were randomly distributed into nine homogenous groups of 75 fish each. Three isocaloric experimental diets differing in protein levels were prepared. The experiment lasted for 8 months and gonadosomatic index, absolute fecundity, egg diameter, number of mature oocytes, hatching rate, larval length, survival rate and amino acid and proximate composition of tissue, liver and ovary were monitored. Growth, gonadosomatic index (GSI) and absolute fecundity increased with increase in protein level. Protein and lipid content of ovary was highest in fish fed 450 g kg-1 protein. The percentage of mature oocyte, highest egg diameter, hatching rate and larval length were highest in the group of 450 g kg-1 protein. There was no significant difference between amino acids profile of muscle in all treatments. Amino acid profile in the liver showed that isoleucine, leusine, phenylalanine and tyrosine were significantly higher in fish fed 450 g kg -1 protein diet.

Some Reproductive Biology Studies of Rabbitfish Siganus canaliculatus (Park, 1797) from the Southern Coastal Waters of Jeneponto, South Sulawesi, Indonesia

The rabbitfish Siganus canaliculatus population has been exploited intensively in the Jeneponto Regency South Sulawesi by fishermen used non selective fishing gear, throughout the year even the spawning season. The intensive fishing without management policy can caused decreasing of the rabbit fish population, and if it continues population will be collapse. This study was conducted to investigate some of the reproductive biological study of this species. A total of 1821 specimens of S. canaliculatus consisting of 1436 males and 385 females were randomly collected on a monthly from fishers in the coastal waters of the Jeneponto, South Sulawesi. The fecundity and gonad stage were studied for 39 female individuals varied between 85 and 284 mm total length (TL). Egg diameters were determined using the microscope. The overall sex ratio (Males: Females) ranged from 1.7: 1 to 8.2:1 The estimation of fecundity was between 5416 and 130760 eggs.ind-1, and increased with fish length, body weight and gonad weight. Egg diameter of S. canaliculatus in this study ranged from 0.1-0.5 of stage III. 0.35-0.45 of stage IV, 0.1-0.55 of stage V, and 0.35-0.55 of stage VI. Egg diameters increased with increased fish length. Egg diameters increased with increased fish length.

Reproductive performance of female Nile tilapia Oreochromis niloticus L. in South Kivu (DR Congo): comparison of two strains differing in origin and history of domestication

This study was conducted to evaluate the reproductive performance of females of Oreochromis niloticus originating from a strain of distant origin and extensively exploited in fish farming (Nyakabera strain) and a local strain recently removed from the natural environment (Lac Kivu strain). The experiment was carried out in triplicate with fry of 4.9 to 6.3 g placed in earthen ponds for a period of 6 months, at the Nyakabera fish station in South Kivu, Democratic Republic of Congo. The comparison of the two strains focused on the size of the first sexual maturity, gonado-somatic ratio, fecundity, egg diameter and condition factor. The results showed that under similar managed rearing conditions, the Nyakabera strain reaches sexual maturity earlier and is characterized by a higher gonado-somatic ratio and higher relative fertility, but a worse condition compared to the Lac Kivu strain. These differences, which indicate a better reproductive success of the Nyakabera strain, are related to the origin and the history of domestication, which are just as different from these two strains.

Dietary supplementation of probiotics and influence on feed efficiency, growth parameters and reproductive performance in female rainbow trout (Oncorhynchus mykiss) broodstock

The aim of this study was to determine the effects of dietary probiotics on reproductive performance, growth, haematological and biochemical parameters of female rainbow trout broodstock. A total of 60 broodstocks with an average initial weight of 2,267.4 ± 54.9 g were divided into four groups and three replicates in raceway ponds. Fish were fed with diets containing 0 (control), 1 × 109 (P1), 2 × 109 (P2) and 4 × 109 (P3) CFU probiotic per kg diet twice a day for 8 weeks before spawning season. Results revealed that higher levels of dietary probiotics (P3) enhanced protein efficiency ratio and decreased feed conversion ratio (p < .05). There were no significant differences in haematological and other growth parameters among different treatments. According to the results, probiotic-fed treatments had the lowest levels of cholesterol (237.7 ± 4.3 mg/dl) and the highest levels of total protein (11.3 ± 0.3 g/dl) and albumin (6.9 ± 0.3 g/dl), so that differences were found between P3 and control groups in all cases (p < .05). Based on the observations from reproductive parameters, the highest egg diameter, working and relative fecundities, fertilization and hatching rates, eyed eggs survival and alevins survival rates up to the absorption of the yolk sac were observed in P3 treatment (p < .05). Moreover, eyeing, hatching and yolk sac absorbing stages in P3 treatment were earlier than those in other treatments (p < .05). The results of present study demonstrated that probiotic supplementation improved reproductive performance and some growth and biochemical parameters in female rainbow trout broodstock and the best performance was observed in fish fed 4 × 109 CFU probiotic per kg diet. Due to an increase in egg production and egg size in probiotic-fed treatments, this feed additive can be used as a suitable ingredient to increase high-quality egg production in rainbow trout breeders.