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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Analýza stáda plemene Highland chovaného v horských podmínkách

HÁLOVÁ, Ludmila January 2016 (has links)
Main aim of the diploma thesis was the analysis of Highland cattle herd and presentation of possibilities of this breed usage in mountain and submoutain areas in the area of the Czech Republic with respect to production of breeding stock and beef. Secondary target was to evaluate the longevity and length of productive life phase of cows of this breed and to describe all management procedures of the studied herd. On the ecological farm with extensive breeding of Highland cattle where the research was done total number of 60 cows and 101 calfs was bred. The structure of cows was analysed according to the year of birth, number of calves, calving interval, age at the first calving and birth difficulty. The average age of cows in the herd was 5 years and maximum number of calves per cow was 11. Calving interval was up to 350 days in 20.4% of the breeding cows, however 14.8% of cows experienced calving interval even more than 710 days. The age at the time of first calving was up to 4 years and the birth difficulty was classified as 100% without any human help. The calves reached in the years 2014 and 2015 an average weight at the age of 120 days 120 kg and 129 kg respectively. At the age of 210 days the weights were 177 kg and 182 kg respectively. The average daily gains were 825 g and 735 g in case of 120 days and 884 g and 772 g in case of 210 days respectively. The difference was not statistically significant. The average weight of steers at the age of 20 months was approx. 335 kg and slaughter weight at 46 months was 563 kg in average. It can be claimed that with appropriate herd management comparable results can be reached under average conditions in the Czech Republic. This also means that a satisfying economic profit is attainable
62

Vliv ukazatelů reprodukce na produkci a kvalitu mléka / Indicators of influence on the reproduction of the level and quality of milk production

Poláčková, Barbora January 2016 (has links)
The aim of this study was to evaluate research of reproduction indicators on the level of milk production and the quality of the milk on selected farm. Materials for processing thesis were obtained on Oldřich Poláček´s Farm Hole. Mr. Poláček´s farm is located in Central Bohemia and manages 380 ha of arabe land. The farm bred Holstein cows, for now there are 190 dairy cows of this breed. The indicators of milk production and reproduction were observed from 2013 to 2015. Results of the observed farm were compared with results of milk yield of Holstein cattle breeders association in the Czech Republic. The data were analyzed and statistically processed using SAS 9.3 (SAS / STAT; 9.3, 2011). To determine the basic parameters of the files were used MEANS procedures and UNIVARIATE. Evaluation of milk yield and indicators of reproduction was based on the results obtained from the recorded milk production of cows done by Holstein cattle breeders association and stable computer system AFIFARM. To evaluate the data were used 104 dairy cows, which had last two standardized lactation completed in the test years from 2013 to 2015 and 121 dairy cows, which had the first standardized lactation completed in 2014 or 2015. For the milk yield were evaluated parameters of kilograms of milk per lactation, kilograms of milk per day, fat (%), protein (%) milk, depending on reproduction (days open, calving interval, age at the first calving) and lactation order. Milk yield on the farm in 2015 was above the national average in Czech Republic. For dairy cows with the first lactation was up to 8 536 kilograms per standardized lactacion, for dairy cows with second lactation was up to 10 928 kg, and for dairy cows with third and more lactation was up to 10 864 kg. The average content of 3,71% fat and 3,28% protein. The influence of lactation negatively impacted % protein (r = -0.278). Conclusiveness was on the significance level (P <0.001). The highest protein content was on the first lactation 3,40%, and lowest in the fifth lactation 3,20%. Statistically failed to demonstrate the influence of the order of lactation on the milk yield per standardized lactation, kilograms of milk and % of fat content. The positive effect was shown between milk yield per lactation in kg and daily milk yield in kg (r = 1). Conclusiveness was on the significance level (P <0,001). The lowest daily milk yield on the first lactation was (30,24 kg) with the production of 9223,06 kg of milk and the highest on the third lactation (47,43 kg) with the production of 14466,76 kg of milk. Increasing of milk production per lactation had a negative effect on the % of fat content (r = -0,137), and % of protein content (r = -0.196). Conclusiveness was on the significance level (P <0.05). With increasing milk production declined % of fat content and % of protein content. Statistically failed to demonstrate the influence of the milk production per lactacion on the open days and the calving interval. Effect was demonstrated between the % of fat content and protein content in % (r = 0,501) at a level of significance (P <0,001). With increasing of fat content in%, increased also the the protein content in %. The lowest protein content (3,20%) was with a 3,66% of fat content. The highest protein content (3,40%) was with a 3,68% of fat content. Age at first calving of dairy cows negatively impacted on % of the fat content of milk (r = -0,186). Conclusiveness was on the significance level (P <0,05). With age increasing at first calving declined % of fat content in milk. There was also demonstrated a connexion between the standardized lactacion and days open (r= 0,227). Conclusiveness was on to the level of significance (P <0,05). With open days increasing the amond of milk per lactacion was higher.
63

Sledování vnitřních vlivů na produkci a kvalitu mléka / Monitoring internal factors on milk production and quality

Králová, Alena January 2016 (has links)
The aim of this thesis was to evaluate the influence of internal influences on the production and milk quality on selected farm. Data for preparation of this thesis were obtained on a farm in Skalica in Frydek-Mistek belonging to the joint-stock company Beskyd Agro. Data used in this thesis were evaluated for two years (1.10.2013-30.9.2014, 1.10.2014-30.9.2015). Data were analyzed and statistically processed using Microsoft Excel software. Evaluation of milk production and reproductive performance were based on the results obtained from regular inspections. For milk yield parameters were evaluated milk yield (kg) Fat (%, kg) Protein (%, kg) of milk somatic cell count (SB) depending upon reproduction and lactation. Evaluated herd were divided into 2 groups: I. lactation, II. lactation and the next lactation. Hypothesis: Worsening indicators of reproduction have negative impact on the level of milk production and its components. The final evaluation of the data were used, comprising 280 cows of Holstein cattle, which were included in monitoring performance period. The results show that the average length of the interim period was around 416 days in average.Milk yield was 10,062 kg of milk with fat contents of 4.21%, 3.37% proportion of protein and somatic cell count 477.75 thousand / ml. The difference in milk yield of heifers at first (9 326.38 kg) and second lactation (9 901.47 kg) reached 575.09 kg. Maximum milk production was achieved on 4th lactation, when milk yield reached 10 432.16 kg per lactation. Positive effect was demonstrated between the % fat content and protein content in%. With the increase in the% fat content, and increased protein content in%. The highest value of the average amount of fat has been statistically proven at 5th lactation and values of 4.18%. For proteins the highest number was reached during the lactation no. 6 with values of 3.40%. The best values were obtained in lactation number 4., where the rate reached the following parameters: milk yield per lactation 10,432, 16 kg daily milk yield: 34.20 kg fat: 4.08% protein: 3.35%. It was determined that the amount of milk yield per lactation in kg was positively affected by the value of the daily milk yield in kg, with the value (r = 1st) verified at a significance level (P <0.001). Increased milk yield per lactation kg should result in an increase daily milk yield. The negative impact was demonstrated in representating % fat content of milk (r = -0.653) and protein (r = -0.442) at the level of significance (P <0.001). Increased milk yield per lactation in kg was negatively effected and reduced the component of fat and protein. Milk yield per lactation had a positive effect on service period. Positive effect on milk yield heifers was demonstrated in service period and with a positive value (r = 0.327) with evidential significance level (P <0.05). Effect of milk yield per lactation, age at first calving was not demonstrated. Effect of daily milk yield in kg of milk, had a negative effect on the proportion of components in % fat (r = -0.653) and protein (r = -0.442). Conclusive came to the level of significance (P <0.001). Increase in daily milk yield will reduce the content of components of protein and fat milk. The positive impact of the daily milk yield was demonstrated in connection with the service period (r = 0.247) at a level of significance (P <0.05). Increasing daily milk yield, this will extend the service period. From the resulting data, negative effect on lactation representation% protein content (r = -0.288) and fat (r = -0.052) with evidential significance level (P <0.001) was determined . Effect of lactation on milk yield per lactation, daily milk yield, calving interval and service period has been shown. Daily milk yield in kg of milk is affected by the amount of milk yield per lactation in kg (r = 1). Conclusive came to the level of significance (P <0.001). Increased milk yield per lactation is proportional to increase of daily milk yield. Milk yield per lactation negatively affected% of fat content (r = -0.187) and% representation of protein (r = -0, 208). Conclusive came to the level of significance (P <0.05). Increasing milk yield per lactation kg reduces% fat and protein. The relationship between milk yield per lactation in kg, service period, and interim periods has not been demonstrated. Effect of daily milk yield in kg, had a negative effect on the% fat content (r = -0, 187) and protein (r = -0.208) with evidential significance level (P <0.05). Reduced% protein content and milk fat is a result of increased daily milk yield in kg. Effect of daily milk yield on service period and the interim has not been demonstrated. Fat content in% and the protein in% (r = 0.603) were demonstrated at a level of significance (P <0.001). Increased if the% fat content, increased the% protein content. The positive effect was demonstrated between service period and interim periods (r = 0.266) with evidential significance level (P <0.001). The longer the period of service increases the length meantime. It was confirmed that with increasing lactation milk yield as per lactation, daily milk yield and milk components content.
64

Vliv vnitřních činitelů na produkci a kvalitu mléka / Effect of internal factors on milk production and quality

Šťásek, Jan January 2016 (has links)
The aim of this thesis was to monitor and evaluate the impact of internal factors on the production and quality of milk in a herd of montbeliarde cattle. The hypothesis was that worse results of reproduction adversely affect milk production. Data collection took place on a farm Osičky agricultural company Agrodružstvo Lhota pod Libčany for the period from 1.1.2010 to 31.12.2015. The file was obtained 1 849 standard lactations completed in this period. The source of data for evaluation of milk production, milk quality and reproductive performance of cows were cards, program Farmsoft from Farmtec used to herd management and output data from the inspections carried out by the utility Chovservis Inc. residing in Hradec Kralove. A statistically highly significant difference (P<0,01) between the first and all other amounts lactation in milk, fat and protein kg per lactation and fat in % and between 1st and 5th and more lactations in % protein. Was a positive effect of length of service period and the length of the intervening period the quantity of milk, fat and protein in kg per lactation at significance level P<0,001 and the negative influence of the length meantime to protein content in % (P<0,001). He was also found at least P<0,001 positive effect on lactation length produced kilograms of milk, fat and protein. Fat and protein also positively influenced the amount of milked milk (P<0,001). It was statistically insignificant effect on the incidence of mastitis production and milk quality (P>0,05), based on correlations may have an adverse effect on the percentage of fat and protein at a higher incidence of mastitis expected. The influence of the proportion of blood Montbeliarde breed was statistically proven only on the amount of milk and protein in kg per lactation, but still pure-bred animals came out the best in all of the indicators except for milk production fat percentage. From comparison of the calving showed that his herd performance increases every year, the quality of milk as the fat content in % but conversely decreases. For the month of calving has been shown to influence the percentage of fat and protein at a significance level of P<0,001, the quantity of milked milk (P<0,01) and the amount of produced protein in kg per lactation (P<0,05). The hypothesis that impaired reproduction results negatively affecting milk production has not been confirmed. It was found to influence reproduction indicators on production and quality of milk, but this influence in a positive direction. The negative effect was demonstrated only for the length of the interim influence on protein content in %. Overall, the level of flock assessed as very good, but there are many indicators of production and reproduction that is necessary with respect to the potential of improving the breed.
65

Analýza některých parametrů reprodukce gepardů (Acinonyx jubatus) chovaných ve světových zoologických zahradách. / The analysis of some reproduction parameters of cheetahs (Acinonyx jubatus) kept in world's zoos.

Makulová, Laura January 2016 (has links)
This work is focused on the breeding of cheetahs Acinonyx jubatus bred in captivity. The first part is divided into two main sections and is processed using the available scientific literature. The first section describes the history and current status of taxonomic classification of individual species and subspecies of the genus Acinonyx. The second section deals with general biology of the species - characteristics, habitat, food in the wild, extending the route of exposure, morphology of the reproductive system. Separate chapters are devoted to the problems of rearing animals in breeding facilities - food cheetahs areas for breeding, a special section discusses the issues of reproduction in captivity. In the practical part, an analysis of data from the International studbook Acinonyx jubatus 2013, focusing on the reproductive success of males and females according to their origin and age. Data was transferred to MS Excel and main observed characteristics presented in the form of graphs. The resulting data were statistically analyzed.
66

Vliv tělesné kondice na reprodukční schopnosti krav plemene Blonde d´Aquitaine / Effect of body condition on reproductive capabilities of Blonde d´Aquitaine cows

Kopečková, Tereza January 2016 (has links)
The purpose of this thesis was to determine the influence and mutual relation between the body condition of cow and the weight of calfs at birth, at 120 and 210 days of age. Next, the influence of the breeding cows body condition on the conception rate was examined. As hypothesis served the assumption that cows with optimal body condition (assesed via the BCS systém, levels 5 and 6) would have the highest conception rate and that their calfs would achieve the expected level of results at the inspection weighting. By contrast, at cows classified by the BCS system as a lower levels e.g. 4 or higher levels e.g. 7 and higher, the conception rate would decrease and the calfs would achieve worse levels at the inspection weighting. For the evaluation, 81 cows with their calves were observed. The beginning of evaluation of the mothers condition began always approximately a week after the calving and further evaluations continued in monthly intervals. In total, six body condition assessments were made with every specimen. For the processing of data, the SAS 9.3 programme was used, namely MEANS, UNIVARIATE, CORR, REG and MIXED procedures. The influence of BCS levels on the weight of calves at birth, at 120 and 210 days of age was not statistically significant (P > 0,05). But if we compare the occuring BCS levels in this work with the stated required range (BCS 5 to 7), the conclusion can be made that the results confirm the hypothesis. Also, a positive correlation occured between the occuring BCS level in the second assesment (P < 0,05) and the weight of calves at 120 days of age, as well as in levels of BCS in first (P < 0,01), second (P < 0,001), third (P < 0,05) assesment and the weight of the calves at 210 days of age. The influence of individual BCS levels on the conception rate was also studied. Here, the influence was also not statistically confirmed (P > 0,05), but the comparison between the occurring BCS levels and the stated optimal range (BCS 5 to 7), the conclusion that the results confirm the hypothesis can be stated. The order of cows calving has statistically important influence on the weight of the calves at birth, at 120 and 210 days of age. The best results were achieved by dams on the 6th and subsequent calving (P < 0,01 and P < 0,05). A positive correlation on the level of importance P = 0,05 was detected, between the order of the calving and pregnancy, but the statistically important influence was not confirmed (P > 0,05). The influence of the calving month on the weight of the calves was confirmed only at weights at 210 days of age. The highest values were achieved by calves born in April (P < 0,01). The influence of sex on the weight of the calves at birth, at 120 and 210 days of age was also studied. Higher values were achieved by bulls (P < 0,05). The weight of the calves at birth affects the calving difficulty. Mothers with calves of lesser weight had demonstrably easier calving (P < 0,01). In the case of difficult calvings, the influence of calves weight on calving was not proven (P > 0,05).
67

Vliv vnějších a vnitřních činitelů na produkci a kvalitu mléka / Effect of external and internal factors on milk production and quality

Chmelíková, Markéta January 2016 (has links)
The aim of this thesis titled "The impact of external and internal factors on the production and quality of milk" was to evaluate these effects in the company. Venture in which those effects are assessed is Kozákov-cooperative in northern Bohemia, on the border of the Bohemian Paradise and Krkonose Mountains foothills at an altitude of approximately 500 m. Kozákov-cooperative behaves Czech Pied cattle. Evaluated were about 290 dairy cows, it is mainly for pasture breeding. This team is not complete the objective of maximum intensity of the yield, but it is also to ensure that the cows produce milk more lactation periods. At present about 200 cows free housing barn in the BIOS, and about 90 cows housed in the stachion stable K 96. In this work we compared the influence of different conditions in the breed and type of housing.
68

Vliv vybraných faktorů na reprodukční vlastnosti dojnic / Effect of selected factors on reproductive characteristics of dairy cows

Šťásková, Michaela January 2016 (has links)
The aim of the thesis was to evaluate the effect of selected factors on the reproductive characteristics of Montbeliard dairy cows. Hypothesis said that high milk production, poor health and high air temperatures have a negative effect on reproductive indicators of cows. In the literature review, there were summarized knowledge about the factors affecting fertility, reproductive indicators and a description of the breed. Observation was carried out on the farm Osičky, which is one of the centers of the company Agrodružstvo Lhota pod Libčany. To assess the influence of milk yield and health were monitored all standard lactations of dairy cows, which were completed in the period from 1. 1. 2014 to 31. 12. 2015. This gave rise to a set of 632 lactations. To evaluate the milk production was data set divided by the number of lactation, quarter of calving and the rate of milk production into three groups. As a disease with an expected negative impact on fertility, mastitis was selected. Besides air temperature, the relative humidity was assessed too. Indicators such as days open, days from calving to calving and services per conception were evaluated. In order to assess the impact of climate change on fertility data file was divided into 3 groups of air temperature, by quarter, according to the category of cows and by calendar year. Services per conception, pregnancy after the first insemination and pregnancy after all insemination, were assessed. Data could be obtained only from a whole herd of cows and heifers. For statistical evaluation has been used SAS 9.3 software (SAS / STAT 9.3, 2011). Achieved an average length of days open was 98.07 days, days from calving to calving 380.62 days, services per conception was 1.94, pregnancy after the first insemination in heifers 54.28% and 48.43% in cows, yield per lactation was 8 407, 98 kg of milk with fat contents of 3.65 % and a protein contents of 3.53 %. Mastitis occurred only in 17.72 % of cases. The average monthly air temperature during the year 2014 ranged from 1.3 ° C to 21.2 ° C, in 2015 it was 1.5 ° C - 23.2 ° C. From the results of the regression analysis, it was found that the milk production per lactation had a statistically significant effect on the length of the days open (r = 0.214; P <0.001), services per conception (r = 0.296; P <0.001) and days from calving to calving (r = 0.147; P < 0.01). Therefore we can talk about the significant influence of milk production per lactation. With the increasing amount of milk kg days open and days from calving to calving extended and services per conception also grew. Analysis of variance confirmed the effect of the amount of milk yield per lactation on days from calving to calving (P <0.05), days open (P <0.001) and services per conception (P <0.001). Furthermore, quarter of calving had a significant effect (P <0.05) on services per conception and days open and the effect of category on pregnancy after all insemination (P <0.01) and services per conception has been demonstrated (P <0.05). Heifers showed demonstrably better results of assessed reproductive characteristics compared to cows. There was no effect of the incidence of mastitis on days open, days from calving to calving and services per conception proven (P> 0.05). Effect of air temperature on services per conception, pregnancy after the first insemination and pregnancy after all insemination, was not statistically proven (P > 0.05). Furthermore it has been approved many correlations between different parameters at the levels of significance (P < 0.001, P < 0.05). The hypothesis was confirmed only for the negative impact of high milk production, but the impact of poor health and high air temperatures on reproduction was not approved. The results indicate a healthy herd in terms of mastitis, good management of breeding, which minimizes heat stress and which is of relatively high milk yield and proven negative impact of high milk production to reproduction, achieved a good level of reproduction.
69

Kontrola užitkovosti masného stáda charolais / Performance recording in Charolais beef herd

Jelínek, Petr January 2016 (has links)
Summary In this thesis I dealt with verification of performance of beef cattle Charolais Breed on farm: Chov Charolais spol. s r. o. Slabce. The main objective of my diploma work was to assess the growth abilities of calves Charolais breed from birth till weaning in relation to various factors, for instance: gender, order of calving, number of born calves during one calving, month and year of the birth on the respective farm. The relevant data was assessed for the period of years 2012 - 2015. In this period there was born 324 calves of which 162 bulls, 153 heifers and 9 still born calves. The assessment of calf's growth characteristics was related to the average birthweight, average gain from birth to 120 days, and average weight at the age of 120 and 210 days. For the evaluation of calf's growth characteristics was used data gained from the database of performance testing of beef cattle (KUMP) for the given period. Growth parameters related to selected factors were processed with the use of statistical software SAS 9.3 (SAS 9.3, 2011). The average weight of young bulls at birth was 33,58 kg and average weight of heifers was 32,99 kg. The average weight of bulls at the age of 120 days was 183,66 kg and the average weight of heifers was 175,58 kg which was demonstrated to be statistically significant (P < 0,01). The average weight of bulls at the age of 210 days was 288,28 kg which is again higher than heifers with average weight of 264,21 kg (P < 0,05). To summarize, there was identified statistically significant difference of the gender influence in behalf of bulls. After comparison of average weight at birth, at the age of 120 and 210 days separately for twins and an only child, there is obvious and also statistically significant finding (P < 0,01) that the observed twins are usually smaller at birth and their growth abilities are worse than that of only child. The average weight at birth for an only child is about 4,48 kg higher compared to twins. Then the average weight at the age of 120 days for an only child is about 38,68 kg higher than average weight of twings. Finally the average weight at the age of 210 days is about 58,26 kg higher for an only child. Regarding to the influence of order of calving there was identified no significant effect to both average birth weight and weight at the age of 210 days. The only statistical significance was identified between order of calving and the average weight at the age of 120 days in 1st, 2nd, 5th, 7th, 10th order of calving (P < 0,05). Further I found out that calves in the 1st order of calving have significantly lower average weight from the 1st calving mothers at the age of 120 days than the calves in the 2nd, 5th, 7th, 10th order of calving. The average weight of calves at the age of 120 days is about 9,29 kg lower than weight of calves in the 2nd order of calving. On the other hand the average weight of calves at the age of 120 days in the 5th order of calving is about 18,37 kg higher than weight of calves in the 1st order of calving. Similarly, calves in the 7th order of calving have about 13,63 kg higher weight than calves from the 1st calving mothers. And also calves at the age of 120 days in the 10th order of calving have about 15,78 kg higher weight than calves from the 1st calving mothers. In respect of influence of year of birth was identified statistically significant different level (P < 0,01) of the average birthweight in year 2013 compared to other years. Similarly there was demonstrated the statistically significant difference (P < 0,01) regarding to the average gain from birth in year 2013 compared to other years. The average birthweight in 2013 was 34,91 kg. The lowest average birthweight of 31,65 kg was observed in 2015. And for instance in 2012 the average birthweight was 32,48 kg which is still about 2,43 kg lower than in 2013. Regarding the evaluation of the average gain from birth till the age of 120 days there was only reported value of 1046,78 g in 2013. The best year regarding the average gain from birth till the age of 120 days was year 2014 which represented value of 1214,37 g. In the observed breed there took place births predominantly from January till June. Regarding the month of birth there was demonstrated statistically significant difference (P < 0,05) in respect of average birthweight of calves born in May 31,98 kg compared calves born in February 32,55 kg and in March 33,07 kg. Further was identified statistically significant difference regarding the average gain from birth for calves born in June 995,28 g compared to calves born in February 1197,87 g (P < 0,01). Similarly in March was reported value of 1181,18 g (P < 0,05). The last statistically significant difference (P < 0,01) was identified in respect of average weight at the age of 210 days of calves born in May 199,55 kg and in June 201 kg in comparison to calves born in January 282,05 kg, in February 284,65 kg, in March 277,21 kg and in April 277,76 kg. To conclude, based on the statistical analysis, conclusive results and literary sources there had been confirmed hypothesis that internal factors positively affect the growth abilities of calves.
70

Strategie oplozování u ryb s vnějším oplozením

SIDDIQUE, Mohammad Abdul Momin January 2016 (has links)
Morphological properties, species specific differences, development, and function of egg envelopes are of importance for a better understanding of fertilization strategies as well as for captive reproduction. We reviewed morphology and the developmental stages of egg envelopes, mechanism of polyspermy block, and also the role of micropyle and cortical granules in polyspermy block for acipenserid eggs. The structure of the egg envelope is similar among the acipenserids, comprising an external envelope (thecal cells, basal lamina, and follicular epithelium), a five-layered oocyte envelope (adhesive layer, alveolar layer, epilayer, and zona radiata externa and interna) and a layer of oocyte matrix and cortical granules. The development of acipenserid egg envelope within the ovary comprises five stages, with further changes following fertilization. Moreover, we standardized the terminology used to describe the egg membranes which can minimize the confusions and be helpful for future work on acipenserids eggs as well as for other fish species. The sperm to egg ratio (required to fertilize eggs) and effects of pre-incubation of eggs in freshwater before fertilization were studied to standardized fertilization protocols for sterlet Acipenser ruthenus. Pre-incubation time had no effect on fertilization success at 430,000:1 and 43,000:1 sperm to egg ratios, while it was significant at the 4300:1 and 430:1 ratios. The use of adequate experimental suboptimal sperm to egg ratio revealed a positive effect of pre-incubation time, such that at the 430:1 ratio, 0.5 min pre-incubation increased the fertilization rate than 10 min. Transmission electron microscopy showed that pre-incubation of eggs in water for <10 min did not trigger a cortical reaction, suggesting that a low sperm to egg ratio 0.5 to 1 min pre-incubation of eggs in freshwater prior to fertilization can enhance fertilization rate of sterlet (minimally do not change fertilization). The effects of pre-incubation in seawater and the duration of egg receptivity were determined for fresh and over-ripe sea bass eggs. Our results revealed a significant effect of pre-incubation time for both the fresh (P < 0.01) and over-ripe eggs (P < 0.01). The fresh eggs had a higher fertilization success than over-ripe eggs. Fertilization success of eggs significantly declined for both of these treatments after 3 min of pre-incubation clearly indicated that sea bass eggs are able to be fertilized by sperm for up to 3 min after release into seawater. Effects of pre-incubation of eggs and activation medium on the percentage of eyed embryos for Ide Leuciscus idus were examined. At the eyed-egg stage, pre-incubation time was significant for the freshwater activation medium (P < 0.001), such that the percentage of eyed embryos declined across the pre-incubation time gradient. Activating medium had a significant effect on the percentage of eyed embryos for each pre-incubation time (P < 0.05). More precisely, freshwater produced the lowest percentage of eyed embryos at all pre-incubation times, whereas saline water and Woynarovich solution produced the highest percentage of eyed embryos at 0 s and 30 s before incubation. Examination of sperm traits showed no impact of activating medium on computer assisted sperm analysis parameters. Our results suggested that saline water or Woynarovich solution improve fertilization rate in Ide during fertilization. In conclusion, this thesis provides basic knowledge on gamete biology, role of egg receptivity period, effects of pre-incubation of eggs and different activating medium which can be useful to understand the fertilization strategies of different externally fertilizing fishes as well as standardize their fertilization protocol for captive reproduction.

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