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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.
11

Effects of Dietary Protein Quality on the Growth of Juvenile Cobia Rachycentron canadum

Lin, Kuo-Wei 01 February 2004 (has links)
Two experiments were conducted to study the effects of dietary protein quality on the growth of juvenile cobia Rachycentron canadum. Experiment I was to find out the maximum level of steam dried blood meal and spray dried blood meal can be used in the diet for juvenile cobia. Experiment II examined how juvenile cobia utilizes supplemental amino acids. In Experiment I, 9 test diets were evaluated. In the first group, steam dried blood meal was used to partially replace fish meal. The replacement levels were 0, 10, 20, 30 and 40% of the fish meal protein. In the second group, crystalline methionine, which was 0.1 and 0.2% of the diets, was added respectively to 2 diets in which 20 and 40% of the fish meal protein was replaced by blood meal. In the third group, spray dried blood meal was used to replace fish meal protein at 20 and 40% instead of steam dried blood meal. Juvenile cobia with an initial weight of 72g were fed with the test diets for 8 weeks. The results showed that the percent weight gain (PWG), specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER) and net protein utilization ratio (NPU) were significantly reduced (P¡Õ0.05) when the replacement level was increased from 20% to 30%. Spray dried blood meal was more effectively than steam dried blood meal was at high replacement level (40%) than low replacement level (20%). Supplementation of crystalline methionine in the cobia diet had no positive effects. In Experiment II, 8 test diets were studied. The control diet contained only fish meal as the sole protein source. The other seven diets all contained steam dried blood meal which replaced 30% of fish meal protein. In the first group of 3 diets, (1) crystalline methionine, (2) crystalline methionine and crystalline isoleucine, (3) crystalline methionine, crystalline isoleucine and crystalline arginine were added, respectively. Two diets were supplemented with (1) microencapsulated (glycerol monostearate) methionine, (2) microencapsulated methionine and microencapsulated isoleucine. Two diets were supplemented with (1) microcoated (cellulose acetate phthalate) methionine, (2) microcoated methionine and microcoated isoleucine. Juvenile cobia with an initial weight of 33g were fed with the test diets for 8 weeks. The results showed that when the fish meal was partially replaced and amino acids were added, the PWG, SGR, FCR, PER and NPU of the cobia were significantly reduced compared to the control group (P¡Õ0.05). In conclusion, steam dried blood meal could effectively replace fish meal up to 20% of the fish meal protein, which was 6.2% of the diet. Spray dried blood meal showed better effects on the growth of fish than steam dried blood meal when given at high level. The two types of blood meal were no difference when the replacement levels were low. Juvenile cobia were not able to effectively use the different types of amino acids evaluated in the experiments.
12

Effects of various soybean products and mineral levels on the growth of juvenile cobia Racycentron canadum

Hsu, Gi-Pin 01 February 2005 (has links)
Two experiments were conducted to study the effects of partially substituting fishmeal with 4 soybean products and mineral supplemental levels in diet of juvenile cobia Racycentron canadum. Experiment ¢¹studied the effects of partially substituting fishmeal with 4 soybean products in diet of juvenile cobia. Experiment ¢º investigated the effects of mineral supplement levels in the growth and body retention of zinc and phosphorus when high percentage of fishmeal in the diet was replaced by hexaned-extracted soybean meal or fermented soybean meal. In Experiment ¢¹, cobia juveniles with an initial weight of 58¡Ó1 g were fed eight experimental diets and a fish meal-based basal diet. The experimental diets were of a 2 (Soybean replacement level: 20 and 40 % of fishmeal protein) ¡Ñ 4 (soybean products) experimental design. The 4 soybean products evaluated were solvent-extracted soybean meal (SES), defatted fermented soybean meal (DFS), soybean meal reduced antinutritional factor (ROS) and soy protein concentrate (SPC). The results of the 8-week feeding trail showed that the growth, FCR, PER and NPU of the fish fed with the 40% ROS diet were significantly worse than these of the other groups. Apparent digestibility (%) of dry matter (ADMD), protein (APD) and lipid (ALD) of all diets were not significantly different. In experiment ¢º, eight experiment diets were tested. The first group was a 2¡Ñ3 factorial design, in which SES replacement levels were 40 and 50%, and mineral supplemental levels were 0.5¡Ñ, 1¡Ñ and 2¡Ñ of the regular supplemental level. The second group tested 50% replacement by FS and mineral supplemental level of 0.5¡Ñ and 1¡Ñ the regular supplemental level. The results of the 8-week feeding trail using the juvenile cobia with an initial weight of 72.3¡Ó0.52 g showed that growth of the fish fed with fermented soybean (FS) diets was significantly inferior to that fed with SES diets at 50% replacement level, especially mineral supplemental levels were 1x or less. The fish fed 2 FS diets were not significantly different on feed conversion ratio, net protein utilization and growth. Protein efficiency ratio of the fish fed with the FS diets was only significantly inferior to that fed 40% 1¡Ñ SES diet. Body and vertebrate zinc concentrations of the cobia that fed FS diets were higher than the SES diet groups. Moreover, the fish fed with SES diets at 40% replacement level were higher than that fed at 50% replacement level. At a same mineral supplemental level, phosphorus concentrations in body of the fish fed with FS diets were higher than that fed SES diet. Phosphorus and ash concentrations in vertebrate of the fish fed with all diets were not significantly different. When replacement level was increased from 20 to 40%, the fish that fed with the SES and DFS diets had better growth and condition factor . Fermentation of soybean increased availability of trace minerals such as zinc. Addition of mineral supplemental 2x levels in diet of juvenile cobia apparent to have negative growth effects. Moreover, 0.5x and 1x levels have the same growth promoting effect. The results suggest that reduction from the regular mineral mixture up to 50 % still support the mineral requirements of the cobia.
13

Study on bacterial flora in liver-kidney-spleen of diseased cobia and grouper with bacteria infection.

Lai, Yueh-Yen 09 November 2005 (has links)
The fish disease epidemiology is urgent to be investigated for the surveillance and prevention. The diseased fish showed splenomegaly with diffusion of white nodules and microscopical granulomatous formation. It is important to develop a method of pathogens isolated from clinical samples with serial dilution method and disc diffusion method. Representative colonies were selected from diseased cobia on BHIA plate and were inoculated onto MacConkey agar, TCBS agar, and blood agar. The cage-culture of the different bacterial groups detected in the survey of bacteria isolated from THOD, HDSB, EMD with serial dilution method. 119 from 128 isolated strains were Gram¡¦s negative (93%), including pathogenic Vibrio spp. 57% (73/128) in THOD. 54 from 90 isolated strains were Gram¡¦s negative (60%), including pathogenic Vibrio spp. 12.2% (11/90) in HDSB. 61 from 104 isolated strains were Gram¡¦s negative (59%), including pathogenic Vibrio spp. 70.2% (77/90) in EMD. In different times diseased grouper, 104 from 139 isolated strains were Gram¡¦s negative (75%), including pathogenic Vibrio spp. 88% (123/139), in 2003. While 24 from 44 isolated strains were Gram¡¦s negative (55%), including pathogenic Vibrio spp. 73% (32/44), in 2004. 66 from 75 isolated strains were Gram¡¦s negative (88%), including pathogenic Vibrio spp. 97% (73/75) by disc dilution method in EMD. 9 from 31 isolated strains were Gram¡¦s negative (30%), including pathogenic Vibrio spp. 26% (8/31), by disc dilution method of grouper in PCG. A DGGE (denaturing gradient gel electrophoresis) technique can identify six groups of bacteria from cobia, and J6, R13, T29 have similarity 100%. Quantity One Version 4.5 (Bio-Rad) can identify six groups of bacteria from diffusion methods that F group diluted the bacterial strain from serial dilution method. B group and E group diluted the bacterial strain from disc diffusion method. Higher resistance rates of the different bacterial strains isolated from cobia and were £]-lactam and susceptible were observed in quinolones.
14

Dietary Methionine and Lysine Requirements of Juvenile Cobia, Rachycentron canadum

Huang, Chih-Chien 12 January 2007 (has links)
Two feeding trials were conducted to study the requirements of juvenile cobia for dietary methionine and lysine. Experiment I compared both fishmeal-based (fish meal and soybean meal as protein sources) and casein-based (casein and gelatin as protein sources) diets. All diets were isonitrogenous and isoenergetic. Crystalline amino acids was pre-coated with carboxymethylcellulose (CMC) and supplemented to simulate the amino acid pattern of juvenile cobia muscle protein except methionine. Five methionine levels of 0.45, 0.70, 0.95, 1.20 and 1.45% (1.07, 1.66, 2.26, 2.86 and 3.45% of protein) were studied. The test diets contained 0.16% cystine. Juvenile cobia (initial weight 35g) were fed test diets for 8 weeks. The results showed that the cobia used fish meal more effectively than casein. Final weight, percent weight gain (PWG), feed conversion ratio(FCR), hepatosomatic index (HSI), condition factor (CF), protein efficiency ratio (PER), protein retention (PR), carcass proximate composition and free methionine concentration in the serum were significantly enhanced (p<0.05) by increasing dietary methionine level. But profile of essential amino acids in the muscle and serum superoxidase and lysozyme activity were not significantly affected. Weight gain of the cobia fed the fishmeal-based diet containing 1.2% methionine was significantly higher than the other dietary groups. Methionine content of 0.45% resulted in reduced growth. No significant difference in weight gain was found in the casein-containing diets when methionine was 0.7% and over. The cobia fed diet containing 0.45% methionine started show apparent skin lesions in their heads on the sixth week of the growth trial and significant mortalities were observed since the seventh week (p<0.05). The optimum dietary level of methionine for cobia, estimated by the broken-line regression analysis on weight gain, was 1.10% (2.62% of protein) based on the fishmeal-based diet results and was 0.70% (1.67% of protein) based on the casein-based diet results. Experiment II used fish meal and wheat gluten as the protein sources. Pre-coated crystalline amino acids were supplemented to simulate the amino acid pattern of juvenile cobia muscle protein except lysine. Lysine levels including 1.49, 1.75, 2.00, 2.25, 2.50 and 2.75% (3.54, 4.16, 4.76, 5.35, 5.95 and 6.54%) were studied. Juvenile cobia (initially 12g) were fed test diets for 8 weeks. The results showed that the final weight, PWG, FCR, CF, PER, PR, carcass proximate composition and free lysine concentration in the serum were significantly enhanced (p<0.05) by increasing lysine levels. But HSI and essential amino acid profile of fish in the muscle were not significantly affected. Final weight and percent weight gain of the cobia fed diets containing 1.75% lysine or over were significantly higher than fish fed diet contained 1.49% lysine. FCR was lower for cobia fed diets containing 1.75% lysine or over than the 1.49% lysine group. The optimum dietary level of lysine, estimated by the broken-line regression analysis on weight gain was 1.76% (4.19% of protein), and was 1.95% (4.64% of protein) on serum free lysine concentration. There was no overt deficiency symptom, such as caudal fin rot in rainbow trout, in the cobia during the growth trial.
15

The Feasibility of Economic Assessment for the Management of Marine Cage Aquaculture in Taiwan

Hung, Hui-Fang 10 September 2008 (has links)
In recent year, marine cage aquaculture has rapidly growing in Taiwan. Fast cage farming development results in expanding scale and production in the limited areas. Concentration farming often causes the degradation and over carrying capacity of marine environment. Thus, the investigation of current operation scale of aquaculture activities is urgently needed by the local authority for the better understanding and planning of aquaculture regulation. The survey were conducted to clarify the management status and to discover the unknown question that are relevant to the farming environment and the Fisheries Right which are waiting further study to resolve. Two major cage aquaculture survey sites, LiouCiou and Peng Hu, have been chosen for interviewing and collection of data. The economic assessment approach provides a tool to the establishment of appropriate strategy and method for the achievement of managing the marine cage operations. Most of aquaculturists in Pen Hu belong to family-owned, in contrast to only one corporate firm which joins the industry for only five years. The corporate firm has less farming experiences than the small scale aquaculturists who have 10-20 years farming experiences. The small scale individual aquaculturists generally have higher survival rate of cobia and efficient productivity of farming. The survey results showed that Peng Hu has longer cage holding period for reaching market size than LiouCiou. According to geographical location, Peng Hu has colder winter temperature and growth delay that require longer time for harvest. The major problem in cage culturing is the impractical and outdated law regulation from the municipal authority. Currently, LiouCiou has invalid regulation regarding to granting the Fisheries Right for culturing. In Peng Hu, the regulation of maximum three hectares per person in law has raised obstacles for aquaculturists who have to acquire someone as dummy account to apply for more farming hectares. Moreover, some still farming aquaculturists have to compete with non-used aquaculturists for granting more site areas where the allowable areas are tied to the limitation by authority. As a result, aquaculturists are devoted to increase the density culture with the risk of over carrying capacity in the limited areas. The study has detected the existing farming problems and presented the following recommendations such as 1) enforcing the implementations of verification, validation, renew and suspension for Fisheries Right, 2) offering low-interest mortgage for farming specially during the weather disaster, 3) enforcing the patrol of marine water to prevent the contraband fish from outside the countries, and 4) designating a farming zone with clear regulation and amended relevantly status quo. At last, aqua culturists should comprehend and adopt the new farming technology, economic assessment, and carrying capacity of farming environment in order to achieve its maximum economic efficiencies.
16

Impact of alternative, non-fish oil dietary lipid sources and subsequent 'finishing' on growth and tissue long-chain polyunsaturated retention in cobia, Rachycentron canadum

Woitel, Franklin 01 August 2013 (has links)
Cobia (Rachycentron canadum) aquaculture is poised for expansion, due in part to rapid growth rate, tolerance of culture conditions, and high market value of this species. Similar to other carnivorous marine fishes, the high monetary cost and long-range unsustainability of reliance on fish oil as the principle lipid source for cobia feeds necessitates evaluation of alternative lipid sources to spare or replace fish oil. Unfortunately, alternative lipid-based feeds may affect production performance, and typically yield fillets with reduced levels of long-chain polyunsaturated fatty acids (LC-PUFAs) such as docosahexaenoic acid (DHA, 22:6n-3). Recent research has indicated that diets rich in saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs), coupled with the application of so-called "finishing feeds" (feeds containing elevated levels of fish oil relative to grow-out feeds) at the end of the production cycle, may limit or attenuate these effects of fish oil sparing. Accordingly, I conducted two trials to evaluate the usefulness of alternative lipids and finishing in cobia culture. In the first trial, I assessed growth performance and tissue fatty acid composition of juvenile cobia fed diets (~11% lipid, ~48% protein) containing fish oil (control), or 50/50 blends of fish oil and alternative lipids (beef tallow, pork lard, partially and fully hydrogenated soy oils, and traditional soy oil) supplemented with an algal meal (to meet the 22:6n-3 requirement of cobia) for 8 weeks. Although minor differences were observed in feed intake, growth performance was otherwise equivalent among the dietary groups. Tissue fatty acid composition varied significantly among treatments, however, with alternative lipids containing higher levels of saturated (SFAs) and monounsaturated fatty acids (MUFAs) yielding tissue profiles that were most similar to those associated with the fish oil-based control feed. Although beef tallow and hydrogenated soybean oil were largely equivalent in terms of growth performance and fatty acid profile change, beef tallow was selected for further evaluation because of its low cost. In the second trial, beef tallow replaced fish oil in feeds at one of four substitution levels: 0% (100% fish oil), 33%, 67%, or 100% tallow (with algal 22:6n-3 meal included in all feeds as before). Juvenile cobia were raised on these feeds for 8 weeks, then switched to the 100% fish oil-based control feed for an 8-week finishing period. During finishing, subsamples of fish were collected every 2 weeks to quantify changes in tissue fatty acid profile over time as a result of finishing. In the second trial, the overall similarity of tissue fatty profiles to those in the 100% fish oil control treatment increased over the course of finishing, mostly as a result of declines in SFAs and MUFAs. These results suggest that SFA and MUFA-rich lipids, such as fully hydrogenated soy oil and beef tallow, are effective and strategically valuable as partial substitutes for fish oil in cobia feeds, and that finishing is at least partially effective in restoring cobia tissue fatty acid composition to a state approximating that of cobia fed only fish oil as dietary lipid.
17

Evaluation of organically certifiable alternate protein sources for production of the marine carnivore, cobia (Rachycentron canadum)

Lunger, Angela Nicole 15 November 2006 (has links)
Cobia represents one of the most attractive candidate species for aquaculture in the history of the industry. With rapid growth rate, high survival rates, and delectable flesh, cobia possess highly desirable characteristics for a cultured fish. Although interest in this species is high, issues pertaining to nutritional requirements must be resolved if this animal is to be produced sustainably. Cobia are high level marine carnivores and, as such, require relatively high dietary protein levels which usually are met through the use of fish meal. Fish meal supplies have become limited and costly, and alternate proteins must be utilized if future aquaculture production is to meet demand. Moreover, the movement towards organic aquaculture production presents additional challenges with respect to fish meal inclusion in aquafeeds designed for cobia. This thesis summarizes research pertaining to fish meal replacement in cobia aquafeeds with organically certifiable alternate protein sources. Initial trials with an organically certifiable yeast-based protein source indicated that up to 25% of the fish meal could be replaced without detrimental impacts to growth rates, feed efficiency, or biological indices. Substitution levels above this resulted in decreased performance in all measured parameters. Based on these results and other research however, it is hypothesized that fish meal replacement levels could be increased to 40% without detrimental impacts upon production characteristics. In a subsequent study, multiple organically certifiable alternate protein sources were investigated for their ability to replace fish meal in aquafeeds for juvenile cobia. A 25% inclusion level of yeast-based protein was used along with a 40% inclusion level. The remaining alternate proteins (soybean meal, soybean isolate, and hemp) also were included at 40% of dietary protein. Two additional diets were formulated to contain all four alternate proteins with or without 8% fish meal. Lack of fish meal resulted in poor survival, while the 8% inclusion of fish meal resulted in decreased overall performance compared to fish fed the fish meal control and the diets with up to 40% organic protein source. When included at 40% of fish meal replacement, these alternate protein sources led to returned excellent weight gain, feed efficiencies, and other production characteristics when compared to the 100% fish meal control diet. I hypothesized that higher inclusion level of alternate protein sources could be achieved with specific amino acid supplementation. Two additional trials involved the use of the yeast-based protein with supplementation by the amino acids methionine, tryptophan, and taurine. Diets containing 50 and 75% of the yeast-based protein were investigated with the addition of methionine (0.3%) and tryptophan (0.2%), with and without taurine (0.5%). Taurine significantly and dramatically increased production performance. A final trial re-evaluated that ability of the yeast-based protein to completely replace fish meal with supplemental taurine (0.5%). While growth at the 50% inclusion level equaled that of the control, at higher levels (75 and 100%), growth was reduced even with taurine supplementation, leading to the hypothesis that other essential amino acids may also have been limiting. This thesis presents evidence that replacement of fish meal, as well as organic production of cobia, is feasible. However, these studies also illustrate the necessity of developing quantitative amino acid requirement data for cobia if these goals are to be fully realized. / Master of Science
18

Suplementação de enzimas exógenas (fitase e protease) em dietas com substituição de farinha de peixe para juvenis do peixe marinho bijupirá (Rachycentron canadum) / Exogenous enzymes (phytase and protease) supplementation in diets with fish meal replacement for juvenile cobia (Rachycentron canadum)

Coelho, Rafael Tsuyoshi Inoe 21 March 2017 (has links)
Foram realizados dois experimentos distintos com juvenis de bijupirá (Rachycentron canadum) alimentados com dietas com substituição parcial da farinha de peixe e suplementadas com enzimas exógenas na (1) fase de berçário em sistema recirculante com duração de sete semanas e na (2) fase de engorda em tanques-rede no mar, com duração de dez semanas, para avaliação de desempenho, retenção copororal e digestibilidade de nutrientes. Foram formuladas e testadas dietas com substituições parciais de farinha de peixe (FM) por farelo de soja (FS), concentrado proteico de soja (CPS) e farinha de vísceras de frango (FV), e suplementadas com duas enzimas exógenas, fitase e protease. No experimento de engorda no mar (peso inicial 240 g; final 500 g), foram testadas cinco dietas, sendo um controle (49% FM) e quatro com substituições de 50 e 60% FM por diferentes níveis de inclusão FS e FV, sendo duas suplementadas com fitase (750 FTU) e protease (600 ppm) e duas somente com fitase (750 FTU). Não foram encontradas diferenças significativas no crescimento, sobrevivência, índice hepatossomático e na digestibilidade de matéria seca, proteína e fósforo para as cinco dietas (p>0.05). O fator de conversão alimentar (FCA) foi melhor com a dieta controle (1,7) do que com suplementação de fitase e protease (2,12) (p<0,05). No experimento com juvenis em fase de berçário cultivado em sistema de tanques recirculante (peso inicial 14 g; final 100 g), foram testadas oito dietas. Em duas dietas-base com substituições de FM por CPS e FV foram adicionados fitase e/ou protease ou fosfato bicálcico, resultando em 7 diferentes combinações, além da uma dieta controle com 49% FM. Ganho de peso, sobrevivência e índice hepatossomático não apresentaram diferenças significativas, enquanto FCA e taxa de aproveitamento de proteína foram significativamente melhores para as dietas com inclusão de CPS do que o controle e as dietas com FV. A adição de fitase, mas não de protease, nas dietas aumentou a digestibilidade de matéria seca, proteína bruta, energia e fósforo nas dietas com ingredientes vegetais. Fitase e protease adicionadas simultaneamente nas dietas aumentaram a digestibilidade dos nutrientes analisados, comparado com a dieta sem suplementação. A adição de enzimas também influenciou na composição corporal dos peixes, principalmente, aumentando a retenção de fósforo e matéria mineral (p<0,05). Os resultados obtidos sugerem a possibilidade de substituições parciais de farinha de peixe nas rações de juvenis de bijupirá por ingredientes vegetais, como o concentrado proteico de soja, ou por ingredientes animais, como a farinha de vísceras, sem implicar em detrimento no desempenho zootécnico dos peixes. Além disso, a adição de enzimas exógenas em dietas com ingredientes vegetais pode trazer ganhos relevantes na digestibilidade e retenção de nutrientes para juvenis de bijupirá, em fase de berçário. / In the present study, growth, body composition, and nutriente digestibility were assessed in juvenile cobia (Rachycentron canadum) fed diets with partial fish meal replacement and exogenous enzymes supplementation. One trial was carried out in recirculated nursery phase for seven weeks and another in the growout phase in net pens in the sea for ten weeks. Test diets were formulated with partial replacement of fish meal (FM) for soybean meal (SBM), soy protein concentrate (SPC), and poultry by-product meal (PBM), and supplemented with phytase and protease. In the growout trial (mean inital weight 240 g; mean final weight 500 g), five diets were tested, one control (49% FM) and four with 50 and 60% FM replacement with different inclusion levels of SBM and PBM, and two supplemented with both phytase (750 FTU) and protease (600 ppm) and two only with phytase (750 FTU). No significant difference was observed in growth, survival, hepatosomatic index and digestibility of dry matter, crude protein and phosphorus (p>0.05). Better feed conversion ratio (FCR) was observed in the control diet (1.7) than with the phytase and protease supplementation (2.12) (p<0.05). Eight test diets were tested in the nursery phase trial (mean initial weight 14 g; mean final weight 100 g). Phytase and/or protease or dicalcium phosphate were added in two base diets with FM replacement with SPC and PBM, resulting in seven different combinations plus a control diet (49% FM). No significant difference was observed in weight gain, survival and hepatosomatic index, whereas FCR and protein retention were enhanced with SPC diet than control or PBM diets. Supplementation with phytase, but not protease, enhanced digestibility of dry matter, crude protein, energy and phosphorus of diets with plant ingredients. Simultaneous supplementation of phytase and protease enhanced nutrient digestibility compared to unsupplemented diets. Furthermore, enzyme supplementation influenced fish body composition, increasing phosphorus and mineral retention (p<0.05). Results suggest the possible partial replacement of FM in the diets for juvenile cobia for plant ingredients, such as SPC, or other animal ingredient, as PBM, with no reduction in fish growth. Also, the addition of exogenous enzymes in diets with plant ingredients may enhance nutrient digestibility and body retention in juvenile cobia in the nursery phase.
19

Suplementação de enzimas exógenas (fitase e protease) em dietas com substituição de farinha de peixe para juvenis do peixe marinho bijupirá (Rachycentron canadum) / Exogenous enzymes (phytase and protease) supplementation in diets with fish meal replacement for juvenile cobia (Rachycentron canadum)

Rafael Tsuyoshi Inoe Coelho 21 March 2017 (has links)
Foram realizados dois experimentos distintos com juvenis de bijupirá (Rachycentron canadum) alimentados com dietas com substituição parcial da farinha de peixe e suplementadas com enzimas exógenas na (1) fase de berçário em sistema recirculante com duração de sete semanas e na (2) fase de engorda em tanques-rede no mar, com duração de dez semanas, para avaliação de desempenho, retenção copororal e digestibilidade de nutrientes. Foram formuladas e testadas dietas com substituições parciais de farinha de peixe (FM) por farelo de soja (FS), concentrado proteico de soja (CPS) e farinha de vísceras de frango (FV), e suplementadas com duas enzimas exógenas, fitase e protease. No experimento de engorda no mar (peso inicial 240 g; final 500 g), foram testadas cinco dietas, sendo um controle (49% FM) e quatro com substituições de 50 e 60% FM por diferentes níveis de inclusão FS e FV, sendo duas suplementadas com fitase (750 FTU) e protease (600 ppm) e duas somente com fitase (750 FTU). Não foram encontradas diferenças significativas no crescimento, sobrevivência, índice hepatossomático e na digestibilidade de matéria seca, proteína e fósforo para as cinco dietas (p>0.05). O fator de conversão alimentar (FCA) foi melhor com a dieta controle (1,7) do que com suplementação de fitase e protease (2,12) (p<0,05). No experimento com juvenis em fase de berçário cultivado em sistema de tanques recirculante (peso inicial 14 g; final 100 g), foram testadas oito dietas. Em duas dietas-base com substituições de FM por CPS e FV foram adicionados fitase e/ou protease ou fosfato bicálcico, resultando em 7 diferentes combinações, além da uma dieta controle com 49% FM. Ganho de peso, sobrevivência e índice hepatossomático não apresentaram diferenças significativas, enquanto FCA e taxa de aproveitamento de proteína foram significativamente melhores para as dietas com inclusão de CPS do que o controle e as dietas com FV. A adição de fitase, mas não de protease, nas dietas aumentou a digestibilidade de matéria seca, proteína bruta, energia e fósforo nas dietas com ingredientes vegetais. Fitase e protease adicionadas simultaneamente nas dietas aumentaram a digestibilidade dos nutrientes analisados, comparado com a dieta sem suplementação. A adição de enzimas também influenciou na composição corporal dos peixes, principalmente, aumentando a retenção de fósforo e matéria mineral (p<0,05). Os resultados obtidos sugerem a possibilidade de substituições parciais de farinha de peixe nas rações de juvenis de bijupirá por ingredientes vegetais, como o concentrado proteico de soja, ou por ingredientes animais, como a farinha de vísceras, sem implicar em detrimento no desempenho zootécnico dos peixes. Além disso, a adição de enzimas exógenas em dietas com ingredientes vegetais pode trazer ganhos relevantes na digestibilidade e retenção de nutrientes para juvenis de bijupirá, em fase de berçário. / In the present study, growth, body composition, and nutriente digestibility were assessed in juvenile cobia (Rachycentron canadum) fed diets with partial fish meal replacement and exogenous enzymes supplementation. One trial was carried out in recirculated nursery phase for seven weeks and another in the growout phase in net pens in the sea for ten weeks. Test diets were formulated with partial replacement of fish meal (FM) for soybean meal (SBM), soy protein concentrate (SPC), and poultry by-product meal (PBM), and supplemented with phytase and protease. In the growout trial (mean inital weight 240 g; mean final weight 500 g), five diets were tested, one control (49% FM) and four with 50 and 60% FM replacement with different inclusion levels of SBM and PBM, and two supplemented with both phytase (750 FTU) and protease (600 ppm) and two only with phytase (750 FTU). No significant difference was observed in growth, survival, hepatosomatic index and digestibility of dry matter, crude protein and phosphorus (p>0.05). Better feed conversion ratio (FCR) was observed in the control diet (1.7) than with the phytase and protease supplementation (2.12) (p<0.05). Eight test diets were tested in the nursery phase trial (mean initial weight 14 g; mean final weight 100 g). Phytase and/or protease or dicalcium phosphate were added in two base diets with FM replacement with SPC and PBM, resulting in seven different combinations plus a control diet (49% FM). No significant difference was observed in weight gain, survival and hepatosomatic index, whereas FCR and protein retention were enhanced with SPC diet than control or PBM diets. Supplementation with phytase, but not protease, enhanced digestibility of dry matter, crude protein, energy and phosphorus of diets with plant ingredients. Simultaneous supplementation of phytase and protease enhanced nutrient digestibility compared to unsupplemented diets. Furthermore, enzyme supplementation influenced fish body composition, increasing phosphorus and mineral retention (p<0.05). Results suggest the possible partial replacement of FM in the diets for juvenile cobia for plant ingredients, such as SPC, or other animal ingredient, as PBM, with no reduction in fish growth. Also, the addition of exogenous enzymes in diets with plant ingredients may enhance nutrient digestibility and body retention in juvenile cobia in the nursery phase.
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Formação e manejo de um plantel de reprodutores do beijupirá (Rachycentron canadum) em Pernambuco

PEREGRINO JÚNIOR, Ronaldo Barradas 28 August 2009 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2017-02-21T16:01:43Z No. of bitstreams: 1 Ronaldo Barradas Peregrino Junior.pdf: 4722999 bytes, checksum: 1eee4688f73c6baee7c2fd8cf17981f6 (MD5) / Made available in DSpace on 2017-02-21T16:01:43Z (GMT). No. of bitstreams: 1 Ronaldo Barradas Peregrino Junior.pdf: 4722999 bytes, checksum: 1eee4688f73c6baee7c2fd8cf17981f6 (MD5) Previous issue date: 2009-08-28 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Cobia (Rachycentron canadum) is a neritic and epipelagic fish that presents an active behavior due to the lack of gas bladder. It is naturally found in tropical and subtropical waters of every ocean, except the eastern Pacific. Due to its high growth rate, good commercial value and fine quality meat, it has a great potential for farming. With this in mind, the Department of Fisheries and Aquaculture, Universidade Federal Rural de Pernambuco (UFRPE), in association with Aqualider Maricultura Ltda., initiated a joint research effort aiming to form a breeding stock based on the capture of wild specimen. Fish were placed in tanks with constant water renewal and/or pure oxygen, and transported to the laboratory (70 km away). Upon arrival at the lab, fish were anesthetized with clove oil (15 to 20 ppm), tagged and their sex was determined through the insertion of a 1 mm cannula. Fish were also bathed in a formaldehyde solution (100 ppt for 30 min) and freshwater (maximum 5 min) against external parasites. Twenty nine fish were captured, from which only seven survived. Deaths were more frequent at the beginning of the study. As tanks were covered and the team acquired more experience, especially in the acclimation procedures and treatment of parasites, a substantial decreased in deaths resulted. Although at the end of the acclimation process the number of breeders was reduced to seven (two females with mean weight of 14-16 kg, four males with around 10 kg each and a specimen with unknown sex), these animals produced 21 fertilized spawns, which resulted in a total of 48.7 million eggs, from which 24 million were fertilized (mean fertilization of 49.3%). Compared to similar attempts to breed wild cobia in captivity, the present results may be considered excellent. It was therefore demonstrated the viability of the methodology employed here in the formation and management of a cobia breeding stock. / O beijupirá (Rachycentron canadum) é um peixe nerítico e epipelágico, de hábito ativo, devido à ausência de bexiga natatória, e com ampla distribuição em águas tropicais e subtropicais de todos os oceanos, exceto no leste do Pacífico. Apresenta um grande potencial para a aquicultura, principalmente pela sua elevada taxa de crescimento, alto valor comercial e carne de ótima qualidade. Em vista disso, o Departamento de Pesca e Aquicultura da Universidade Federal Rural de Pernambuco, em parceria com a Aqualider Maricultura Ltda., iniciou os trabalhos de criação desta espécie por meio da formação de um plantel de reprodutores, a partir da captura de indivíduos selvagens. Os peixes capturados foram colocados em tanques com renovação de água e/ou oxigênio puro, transportados até o porto e, por via rodoviária (cerca de 70 km de distância), até o laboratório da Aqualider, no município de Ipojuca, PE. Após anestesia com óleo de cravo (15 a 20 ppm), foi realizada a identificação com marcas plásticas tipo TAG e o sexo determinado através da inserção de uma cânula de aproximadamente 1 mm no orifício urogenital do peixe. Após a reanimação da anestesia, os peixes foram profilaticamente tratados com solução de formol (100 ppm por 30 min) e água doce (máximo 5 min) para retirada de possíveis ectoparasitos. Vinte e nove exemplares foram capturados, dos quais apenas sete sobreviveram. As mortalidades foram mais frequentes no início das capturas. Com a cobertura dos tanques e a maior experiência da equipe, principalmente no manejo e nos procedimentos de aclimatação e tratamento contra parasitas, foi observada uma diminuição significativa na mortalidade. Apesar do número reduzido de reprodutores ao final do processo de aclimatação (duas fêmeas com peso médio de 14 a 16 kg, quatro machos com peso médio de aproximadamente 10 kg e um exemplar sem sexo definido), estes animais produziram 21 desovas fertilizadas e nenhuma desova infértil, as quais resultaram em um total de 48,7 milhões de ovos, dos quais, 24 milhões foram ovos fertilizados (taxa média de fertilização de 49,3%). Em comparação com estudos similares, os resultados aqui obtidos podem ser considerados excelentes. Fica, portanto, demonstrada a viabilidade da metodologia aqui empregada na formação do plantel e manejo de reprodutores de beijupirá.

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