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The effect of dietary protein source on the metabolism and performance of ewes in late pregnancy and early lactationHandford, David January 2001 (has links)
No description available.
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Peruvian fishmeal industry resilience to El Niño Southern Oscillation (ENSO) Events: Implications for industry structureLeiva Lanza, Paul January 1900 (has links)
Master of Science / Department of Agricultural Economics / Aleksan Shanoyan / With the recent increase in record-breaking weather events and the inherent susceptibility of the fishmeal industry to temperature fluctuations, the industry dynamics and sustainability of the Peruvian fishmeal sector has gained renewed attention. Among important causes of concern are the cyclical impact of El Niño Southern Oscillation (ENSO) events on productivity and profitability of fishmeal producing firms, long-term structural changes in the industry, and resulting socio-economic consequences. Although distinct risk management strategies have been implemented by industry players and a range of policy initiatives have been introduced by the government over the years, the firms in the Peruvian fishmeal industry remain highly susceptible to the effects of ENSO events. The increased frequency and magnitude of ENSO events over the past decade has forced relatively less resilient firms out of business and has been accompanied by an observable trend towards increased industry concentration. While there is a potential for efficiency gains and economies of scale from increased concentration, policy makers and industry players have concerns about negative social implications from declining numbers of small and medium firms and shifting competitive dynamics in the industry. As a result, policy-makers and industry stakeholders are in the continuous search for effective strategies and mechanisms for enhancing the resilience of individual fishmeal producers and the overall industry to the effects of ENSO events.
The objective of this study is to expand the understanding of factors that affect the resilience of firms to ENSO events in the Peruvian fishmeal industry. The analysis is based on a panel database that combines information from the Peruvian Instituto Nacional de Estadística e Informática (Statistics Institute), Aduanet (Peruvian Customs website), and the Oceanic Niño Index (ONI). The objective is to identify firm characteristics and factors that can potentially enhance the resilience of a firm to the negative impacts of ENSO events. The specific period of study covers the ENSO event that lasted from July 2009 to April 2010. The resilience of individual firms is measured by applying system resilience framework proposed by Barroso et al. (2015). Subsequently, the effect of a range of characteristics on firm resilience is estimated using a fractional response logit method. Among key parameters of interest are the estimated effects of size, experience, location, and participation in government support programs. The results indicate positive relationship between resilience and experience, diversification, access to government subsidy programs, and share of imported inputs. The results also indicate a negative effect of firm size on resilience to ENSO events. The industry and policy implications of the findings are discussed, while highlighting the number of methodological limitations. The overall contribution of this study is twofold. First it presents an application of resilience triangle approach to measuring firm resilience in the context of Peruvian fishmeal industry. Second, it provides new insights on the factors affecting firm resilience to the negative impact of ENSO events. The findings have a potential to inform policy and industry initiatives designed to enhance the industry’s ability to cope with negative consequences of ENSO events.
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Investigation of the Nutritional Requirements of Australian Snapper Pagrus Auratus (Bloch & Schneider, 1801)Booth, Mark Anthony January 2005 (has links)
This thesis describes research designed to increase our knowledge of the nutritional requirements of Australian snapper Pagrus auratus and provide information on the potential of Australian feed ingredients to reduce the level of fishmeal in diets for this species. The apparent digestibility of organic matter (OM), crude protein (CP), crude fat (CF) and gross energy (GE) from selected animal, cereal or oilseed meals incorporated at different inclusion levels was determined. Snapper were extremely efficient at digesting the CP, CF and GE from fishmeal and rendered animal meals (range 80-100%) with the exception of meat meal, where CP and GE digestibility were lower (62-65%). The CP from oilseeds was better digested (87-91%) than OM (57%) or GE (64-67%). Digestibility of nutrients and GE from animal meals and fish oil was not influenced by inclusion level. The CP from extruded wheat was highly digestible (100-105%), but, the OM, CF and GE digestibility of extruded wheat declined as inclusion levels increased. The interactive effects of inclusion level (150, 250, 350 or 450 g kg-1) and fish size (110 vs 375 g snapper) on the apparent digestibility of OM and GE from gelatinised wheat starch were investigated. The OM and GE digestibility of gelatinised wheat starch was high (89%) at low inclusion levels, but declined significantly in both fish sizes as the level of starch increased. There was no interaction between inclusion level and size of fish and the decline in GE digestibility could be predicted by the regression; GEADC = 104.97(±3.39) - 0.109(±0.010) x inclusion level (R2=0.86). Larger fish were more capable of digesting the GE from gelatinised starch than smaller fish. Regardless of fish size, short and longer-term changes in the physiology of snapper fed or injected with carbohydrates were recorded. Liver and tissue glycogen concentrations and the hepatosomatic index (HSI) of snapper fed gelatinised starch were significantly elevated. The plasma glucose concentrations of fish injected intra-peritoneally with D-glucose increased from resting levels (0.4-4.6 mM) to 18.9 mM approximately 3 hours after injection and fish displayed a hyperglycaemic response for nearly 18 hours. In contrast, the post-prandial response to the uptake of glucose from normally digested gelatinised starch was more regulated. A dose-response study to determine the effects of digestible energy (DE) content (15, 18 or 21 MJ kg-1) on the digestible protein (DP) requirements of juvenile snapper was assessed using a four parameter mathematical model for physiological responses (4-SKM). DP content of test diets ranged from 210 to 560 g kg-1. Weight gain and protein deposition was strongly dependent on the ratio of DP:DE. According to the fitted models, diets for snapper weighing between 30-90 g and reared at temperatures ranging from 20-25ºC should contain a minimum of 28 g DP MJ DE-1 to promote optimal weight gain and protein deposition. The effect of varying the absolute content of DP and DE on the weight gain and performance of snapper (100-300 g) fed diets formulated with an optimal ratio of DP:DE was investigated. In addition, non-protein sources of DE were varied by adjusting the ratio of fish oil to gelatinised wheat starch in order to determine if different ratios of these ingredients affected performance. High-energy diets (22-23 MJ DE kg-1) suppressed feed intake, but provided DP intake was not limited by feed intake, maximum weight gain was approached. Lower-energy, lower-protien diets (15-18 MJ DE & 315-390 DP) encouraged higher feed intake but DP intake was restricted, which reduced growth potential. Snapper performed best on high-energy, high-protein diets (490 DP & 21 MJ DE), provided a significant proportion of DE was supplied as DP. Fish oil and pregelatinised wheat starch could be interchanged according to their DE values without unduly affecting fish performance in diets providing 390-490 g DP kg-1. Two utilisation studies were undertaken to investigate the performance of snapper fed diets containing increasing levels of poultry offal meal, meat meal and soybean meal. All diets were formulated with similar DP and DE contents. Snapper readily accepted feeds containing high levels of poultry meal (360 g kg-1), meat meal (345 g kg-1) or soybean meal (420 g kg-1), before weight gain and performance was negatively affected. In combination, these feed ingredients were able to replace all but 160 g fishmeal kg-1 in commercially extruded test feeds for this species. The research described in this thesis has extended knowledge of the nutritional requirements of Australian snapper by providing important information on the digestibility of Australian feed ingredients. These coefficients have been integral in formulating both experimental and semi-commercial test diets for snapper and will increase both the accuracy and flexibility of commercial diet formulations for this species. High performance feeds for snapper will contain high levels of DP, but must provide a significant proportion of DE in the form of protein. These constraints can be satisfied by using alternative, well-digested protein and energy sources that have the potential to replace all but 160 g kg-1 fishmeal.
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Fishmeal supplementation to high producing Jersey cows grazing ryegrass or kikuyu pastureMalleson, Evelyn Rhoda 27 June 2008 (has links)
Rumen-undegradable protein might be the first limiting nutrient for high producing dairy cows receiving high levels of maize supplementation while grazing pasture. To test this hypothesis two trials were conducted using fishmeal as a high quality protein source rich in rumen-undegradable protein, Methionine and Lysine. In the first trial cows grazed annual ryegrass for two months in spring. In the second trial cows grazed kikuyu for two months in late summer. In addition to the pasture cows received 6 kg (as is) of a maize-based supplement, including minerals, fed in two equal portions in the milking parlour. A randomised complete block design was used. Three groups of 15 (ryegrass) or 14 (kikuyu trial) cows received control (no fishmeal), low fishmeal (4 % fishmeal replacing maize) or high fishmeal (8 % fishmeal replacing maize) treatments. Multiparous, high producing, Jersey cows in early to mid lactation were used. Milk production was measured and milk samples taken fortnightly. Simultaneous studies were conducted using eight rumen cannulated cows receiving the control and high fishmeal treatments in a cross over design experiment. Ruminal pH, ammonia-N and volatile fatty acid concentrations were measured. In the ryegrass trial milk yield, 4 % fat-corrected milk yield and milk fat and protein percentages of cows on the low and high fishmeal treatments (21.9 and 22.1 kg milk/d, 24.1 and 24.2 kg 4 % fat-corrected milk/d, 4.73 and 4.67 % fat and 3.49 and 3.45 % protein) were significantly higher than the control (20.5 kg milk/d, 20.4 kg 4 % fat-corrected milk/d, 3.97 % fat and 3.25 % protein). There was no treatment effect on milk urea N (16.8, 17.4 and 17.9 mg/dl, for the control, low fishmeal and high fishmeal treatments, respectively). The ruminal ammonia-N concentration was significantly higher in the cows on the high fishmeal treatment than the control (16.67 vs. 14.16 mg/dl). Fishmeal supplementation to cows on ryegrass is profitable under any realistic price scenarios in South Africa. In the kikuyu trial cows on the high fishmeal treatment produced significantly more milk (19.5 kg/d) than the cows on the control (18.2 kg/d), neither differing from the low fishmeal treatment (18.9 kg/d). The cows on the low fishmeal treatment had significantly higher milk fat percentage (4.18 %) than the control (3.71 %), neither differing from the high fishmeal treatment (3.91 %). The cows on the two fishmeal treatments produced significantly more 4 % fat-corrected milk than the control (19.4 and 19.2 vs. 17.3 kg 4 % fat-corrected milk/d). There was no treatment effect on milk protein percentage (3.30, 3.41 and 3.34 % for the control, low and high fishmeal treatments, respectively). Milk urea N was significantly higher for the high fishmeal treatment (10.80 mg/dl) than the control and low fishmeal treatments (9.09 and 9.44 mg/dl). Ruminal ammonia-N concentration was significantly higher in the cows on the high fishmeal treatment than the control (6.52 vs. 4.74 mg/dl). Fishmeal supplementation to cows on kikuyu could be profitable under certain price scenarios. / Dissertation (MSc(Agric) (Animal Science))--University of Pretoria, 2008. / Animal and Wildlife Sciences / unrestricted
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Assessing environmental sustainability and value addition opportunities for by-products from aquacultureNewton, Richard W. January 2014 (has links)
By-products and mortalities from aquaculture have often posed significant challenges to the industry because of their low value resulting in high costs and environmental impact from their disposal. However increasing interest is being expressed in their utilisation to add value to the aquaculture industry and provide synergies with industries which had previously been in competition with aquaculture. Current and prospective processing by-product and farm mortality utilisation strategies were reviewed along with regulations and standards which aim to control their use and protect against human and animal health hazards. The role of aquaculture and fishery by-products in the supply of fishmeal was investigated and it was found that both sectors had the potential to contribute to increasing global supply. There were significant quantities of processing by-products identified which could be directed to fishmeal manufacture but there were also significant amounts of fish production which were not being processed in some regions and could also add to supplies. Processing by-products from aquaculture species often exceed 50% of the production by mass and therefore their efficient utilisation is of significant importance to the overall performance of the value chain. Their utilisation strategies are diverse and in some circumstances offer the possibility to add significant value. Life Cycle Assessment (LCA) is increasingly being used to inform decision makers and consumers about the environmental performance of goods and services to make choices on best practices and informative decisions on purchasing choices. Current methodology in LCA was critiqued and developed to be used for identifying disproportionate impacts from by-product industries and comparative assessment of the eco-efficiency of value chains from Thai shrimp, Vietnamese Pangasius catfish and Scottish salmon aquaculture. New LCA methodology was developed assessing the eco-efficiency of co-products as a whole and in relation to a tonne of edible yield. Measuring the impact of the by-product industry in relation to their edible yield gave different results to measuring their eco-efficiency between the three study species. It was found that the Thai shrimp value chain was the most eco-efficient when by-products were directed to chitosan and hydrolysate manufacture, but production of the salmon was the least impacting between the species in terms of edible yield. Pangasius was the most environmentally impacting of the three species value chains using both methods. It was also found that the upstream impacts of fish and shrimp production, especially feed manufacture, contributed most to the environmental impact in most circumstances, using both economic and mass allocation. Although the methodology produced interesting results, there were some drawbacks and the data sets also had several gaps which led to some assumptions, which could have skewed the results and interpretation. The cause of mortality for five aquaculture species in five countries and their subsequent utilisation was investigated. It was found that extensive systems were more prone to mortality than intensive systems in many cases. There was a wide range of strategies for mortality utilisation. In countries where by-product industries existed, farmers were often able to sell some of their mortality losses but in other areas, disposal could create health and biosecurity hazards. In conclusion, it was found that both by-products and aquaculture mortalities could be utilised effectively and that the additional impact from their use was low in proportion to the rest of the value chain.
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Factores determinantes que impactaron en la evolución de las exportaciones de la harina de pescado con partida arancelaria 2301.20.11.00, hacia el mercado de la República Popular China, en el marco del tratado de libre comercio Perú-República Popular China en el período 2012-2017Osores Camarena, Yonel Marcos, Wiese Armebianchi, Luis Guillermo 31 January 2019 (has links)
El Perú ha fortalecido su política comercial a través del potenciamiento del comercio exterior. Mediante la apertura comercial, el Perú puede llegar a los diferentes mercados del mundo. Entrar en negocios internacionales incrementa la eficiencia productiva de los países, pues los países exportan aquellos productos que le resultan más económicos de producir e importan aquellos productos que le resultan más costosos de producir. Además, los Tratados de Libre Comercio, permiten el desarrollo del Perú en términos económicos, culturales, políticos, legales, sociales, ambientales y tecnológicos. El Programa País, el PENX y la Agenda Complementaria, son un claro ejemplo de que nuestra política comercial sigue en búsqueda de la consolidación.
En este contexto, el Perú cuenta con un Tratado de Libre Comercio con la República Popular China (de ahora en adelante China), el cual entró en vigor el 01 de marzo de 2010 (TLC Perú-China, 2011). Nuestras exportaciones hacia dicho país han aumentado considerablemente en volumen y valor FOB (ADEX DATA TRADE, 2018) y China es nuestro principal socio comercial con una amplia ventaja. En el sector pesquero, la Harina de Pescado es el producto líder en exportaciones mundiales. La materia prima de la harina de pescado es la anchoveta y la pesca de esta especie, tuvo un momento clave cuando se establecieron los límites máximos de captura por embarcación, en búsqueda de la sostenibilidad del recurso (Aranguren, Arteaga y Chavez).
Por otro lado, el mercado de China tiene una alta demanda de la harina de pescado, la cual es destinada al principalmente al desarrollo de la acuicultura, que se basa en la crianza de especies acuáticas (Pullin y Rashid, 2005). El gigante asiático presenta entonces un alto desarrollo en dicha actividad económica y cuenta a su vez con la mayor población del mundo, la cual asciende a 1, 386, 395 millones de habitantes (Banco Mundial, 2018).
En el presente trabajo de investigación, se realizará un análisis de los factores más determinantes que impactaron en la evolución de las exportaciones de la harina de pescado, en el marco del TLC Perú-China, en el período 2012-2017. / Peru has strengthened its trade policy through the strengthening of foreign trade. Through commercial opening, Peru can reach the different markets of the world. Entering international businesses increases the productivity of countries, since countries export those products that are more economical to produce and import those products that are more expensive to produce. In addition, the Free Trade Agreements allow the development of Peru in economic, cultural, political, legal, social, environmental and technological terms. The Country Program, the PENX and the Complementary Agenda are a clear example that our commercial policy is still in search of consolidation.
In this context, Peru has a Free Trade Agreement with the People's Republic of China (hereinafter China), which entered into force on March 1, 2010 (Peru-China FTA, 2011). Our exports to that country have increased considerably in volume and value FOB (ADEX DATA TRADE, 2018) and China is our main trading partner with a wide advantage. In the fishing sector, fishmeal is the leading product in world exports. The raw material of the fishmeal is the anchoveta and the fishing of this species, had a key moment when the maximum limits of capture by boat were established, in search of the sustainability of the resource (Aranguren, Arteaga and Chavez).
On the other hand, the Chinese market has a high demand for fishmeal, which is mainly destined to the development of aquaculture, which is based on the rearing of aquatic species (Pullin and Rashid, 2005). The Asian giant then has a high development in this economic activity and has in turn the largest population in the world, which amounts to 1, 386, 395 million inhabitants (World Bank, 2018).
In the present research work, an analysis of the most determining factors that impacted the evolution of fishmeal exports will be made, within the framework of the Peru-China FTA, in the period 2012-2017. / Tesis
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Evaluation of Whole and Lipid-Extracted Algae Meals (LEA) in the Diet of Juvenile Red Drum (Sciaenops ocellatus) and Digestibility of LEA by Red Drum and Hybrid Striped Bass (Morone chrysops x Morone saxatilis)Patterson, Donovan Aaron 03 October 2013 (has links)
As aquaculture continues to expand, protein sources have become more costly and less available. Simultaneously, lipid-extracted algal meals (LEA) (co-products of bio-diesel production) are becoming increasingly available as alternative sources of energy are investigated. By integrating LEA into aquaculture diets, feed prices could be lowered and bio-diesel production would have an additional revenue stream.
Three feeding trials each of 7 weeks duration were conducted to evaluate five different algal meals as partial replacements for fishmeal and soy protein concentrate in diets for juvenile red drum (Sciaenops ocellatus). Apparent digestibility coefficients (ADCs) for CP and energy in various LEAs also were determined with red drum and hybrid striped bass (HSB).
In the first trial, whole algae meal and LEA derived from Navicula sp. replaced 5 or 10% of the crude protein (CP) in the reference diet. Weight gain, feed efficiency (FE), hepatosomatic index (HSI), as well as protein and energy retention were not significantly (P>0.05) affected by the dietary treatments. Algal inclusion significantly affected the ADCs of the various dietary treatments for dry matter, CP, and energy. The inclusion of ash in the form of diatomaceous earth improved digestibility of protein as well as weight gain, survival and FE.
A second feeding trial evaluated LEA derived from Chlorella sp. processed at high temperatures, replacing 5, 10, 20, and 25% of the CP in the reference diet. Weight gain, FE, survival, and protein efficiency ratio (PER) were significantly reduced at substitution levels of 20 and 25%. The third feeding trial evaluated LEA derived from Nanochloropsis salina, replacing 5, 7.5, 10, and 15% of the CP in the reference diet. Weight gain, FE, survival, and PER were significantly affected by some dietary treatments, with the 15% substitution levels causing significant reductions in performance. Intraperitoneal fat ratio and whole-body lipids were significantly lower in the fish fed the 15% substitution diet.
Based on the results of these experiments, replacement of up to 10% of CP from fishmeal and soy protein concentrate with LEA was possible without causing substantial reductions in fish performance, and the whole algae product provided a more nutritious product. Red drum and HSB showed similar responses in their ability to digest CP and energy from the various algal products, although ADCs varied greatly among the different products and processing methods.
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Integrated processing of brewer's spent grain into value-added protein feedstuff and cellulose adsorbentHe, Yanhong 16 September 2021 (has links)
Brewer's spent grain (BSG) is the major byproduct generated by the brewing industry, which contains 14–30% protein and 50–70% of fiber. Currently, BSG is predominantly used as low-value cattle feed or buried in landfills, which is a considerable loss of valuable resources, leading to economic loss and environmental problems. Although research has been done on BSG valorization, the studies are limited to producing a single product (e.g., polyphenols, ethanol, or active carbon) and without further utilization of the produced products. Besides, the economic information available about the production of value-added products from BSG is insufficient. The overall goal of this research is to develop an integrated process to convert BSG into value-added protein-rich feedstuff and cellulose absorbent. The objectives of the research detailed here were to 1) develop a process to simultaneously produce protein-rich (PP) and fiber-rich products (FP) from BSG, 2) assess the replacement of fishmeal with PP in shrimp feed, 3) evaluate the economics of the overall process of PP production at a commercial scale, and 4) explore the potential use of cellulose adsorbent obtained from the FP in removing heavy metals from contaminated water.
To attain these objectives, BSG was first subjected to a wet fractionation process to produce PP and FP using different chemical/biological treatments, where the effects of sodium hydroxide, sodium bisulfite, and a protease (Alcalase) at different concentrations were investigated. Under the optimized conditions, the produced PP contained 46% protein and less than 1% fiber. The effectiveness of using PP to replace fishmeal at increasing levels (10–70%) was then evaluated by performing shrimp feeding trials. The results showed that up to 50% of fishmeal in shrimp feed can be replaced by PP without affecting shrimp growth and feed utilization. Moving forward, a techno-economic analysis was conducted to evaluate the economic feasibility of the production of PP. The experimental conditions and results were input into the process simulation model for determining the mass and energy flows. For a processing plant with a capacity of 590 t wet BSG per day, the minimum selling price of PP to achieve a 5% return was determined to be $1044/t, lower than the price of fishmeal, indicating that the use of PP to replace fishmeal in shrimp feed could potentially reduce shrimp farming cost. The utilization of FP will further improve the economic feasibility of the fractionation process. FP was sequentially treated by dilute acid, alkali, and bleach to produce purified cellulose fibers, which were then modified by 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) oxidation to produce a cellulose adsorbent. The feasibility of the adsorbent in removing heavy metals (especially lead and manganese) from contaminated water was then investigated. Based on the results, the produced cellulose adsorbent showed high adsorption capacities for lead (272.5 mg/g) and manganese (52.9 mg/g). Overall, this study demonstrated that BSG can be upcycled into multiple value-added products via an integrated process. The outcomes of this study not only provide a low-cost and sustainable protein source to the aquaculture industry, and provide a novel adsorbent for the water treatment industry, but also offer alternative ways for the brewing industry to manage BSG. / Doctor of Philosophy / Brewer's spent grain (BSG) is the major byproduct generated by the brewing industry. Currently, BSG is predominantly used as low-value cattle feed or buried in landfills due to its high fiber and low protein contents, which is a considerable loss of valuable resources. Besides, raw BSG contains other nutrients and high water content, the inappropriate management of BSG may introduce environmental concerns. Though technologies have been investigated to valorize BSG by extracting protein from it, the process scaled-up is limited by the high drying costs of wet BSG, heavy chemical consumptions, and a large amount of fiber residue. The overall goal of this research is to develop an integrated process to convert BSG into value-added protein-rich feedstuff and cellulose absorbent.
In this study, we developed and optimized a process to produce protein and fiber products from wet BSG. The protein content of the produced protein product was doubled and the fiber content was reduced significantly compared with the raw BSG, which lighted the use of the protein product as an alternative to fishmeal. Fishmeal is an expensive aquafeed ingredient, the aquaculture industry is looking for alternatives to replace it. Herein, we investigated the effectiveness of the protein product as an alternative to fishmeal by conducting shrimp trials. A further economic analysis was conducted to evaluate the economic feasibility of the proposed process for protein and fiber production from BSG. In addition, the fiber product was used for producing a cellulose adsorbent to remove heavy metals from contaminated water.
Overall, this study demonstrated that BSG can be upcycled into multiple value-added products via an integrated process. The outcomes of this study not only provide a low-cost and sustainable protein source to the aquaculture industry, and provide a novel adsorbent for the water treatment industry, but also provide alternative ways for the brewing industry to manage BSG.
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Family growth response to fishmeal and plant-based diets shows genotype x diet interaction in rainbow trout (Oncorhynchus mykiss)Pierce, Lindsey Renea 31 July 2008 (has links)
The ability of rainbow trout to efficiently utilize plant-based diets for growth and the genetic variation for that trait have not been thoroughly examined. In this study, growth of a pedigreed population from the commercial Kamloop strain was assessed while feeding plant-based or traditional fishmeal-based diets. Both fish oil (5.00%) and soybean oil (8.43%) were included in the plant-based diet, and only fish oil was used in the fishmeal diet (10.10%). Ninety-five full-sib families nested within 47 half-sib families were reared in a common environment. Parentage assignment was performed on approximately 1,000 fish fed each diet using eight microsatellite markers chosen for non-duplication, a minimum of five alleles with no known null alleles, at least 50% heterozygosity, and unambiguous scoring. Progeny were assigned to parental pairs using two allocation programs, PAPA and FAP, to increase accuracy and to test assignment efficiency. The fish fed the fishmeal/oil diet were approximately 8% larger than the fish fed the plant-based diet (P < 0.05). A significant genotype x diet effect accounted for 5% of the random variation. The genetic correlation for growth on the two diets was 73%, with a heritability of 30% across the diets. With this, I conclude that substantial genetic variation for utilizing pant-based diets containing soybean meal and oil exists in this widely used commercial rainbow trout strain. The genetic variation can be explored to detect and select for genes involved in proved utilization of plant-based diets containing soybean meal and oil if growth on plant-based meals becomes a long-term breeding goal in rainbow trout production. / Master of Science
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Validation of the Fung double tube to enumerate Clostridium perfringens from the intestinal contents of broiler chickens raised on different dietsBarrios Godoy, Miguel Alejandro January 1900 (has links)
Master of Science / Department of Animal Science / R. Scott Beyer / Daniel Y.C. Fung / Clostridium perfringens causes necrotic enteritis (NE), resulting in decreased feed efficiency and increased mortality, costing the poultry industry USD 2 billion a year worldwide. The objective of the first trial was to validate the Fung Double Tube (FDT) to detect and enumerate C. perfringens in chicken intestines. Two methods (FDT and petri plates) and three media (Shahidi Ferguson Perfringens [SFP] with egg supplement, polymyxin B [p], and kanamycin [k; E]; SFP with p and k [P]; and SFP with cycloserine [C]) were arranged in a 2 x 3 factorial, resulting in six treatments. The FDT with medium C (5.35 log CFU/g) had significantly (P<0.05) higher C. perfringens counts than any other media/method combination. The objective of the second and third trials was to determine the effect of diet type on the population of C. perfringens in broiler intestines using the FDT. Trial 2 tested: corn-soybean meal (SBM), low-crude protein (19.8%)/high synthetic amino acids (SAA), and barley (56%)-fishmeal (4%; BF). Diets in Trial 3 included: corn-SBM, barley (7.46%), fishmeal (4%), and BF. Diets in Trial 2 contained an antibiotic and a coccidiostat; diets in Trial 3 did not. After 21 days, birds in Trial 2 fed BF had significantly higher (P<0.05) counts (5.96 log CFU/g) of C. perfringens, as compared to all other diets. Both, corn-SBM and SAA diets resulted in 3.89 log CFU/g. In Trial 3, birds fed the corn-SBM diet (2.7 log CFU/g) had significantly lower (P<0.05) counts than broilers fed BF (4.15 log CFU/g). When broilers were fed fishmeal (3.583 log CFU/g) and barley (3.577 log CFU/g) separately, C. perfringens counts were numerically higher compared to the corn-SBM diet, but numerically lower than birds fed BF. Barley and fishmeal inclusion increased the incidence of C. perfringens, and their combination resulted in a cumulative effect. The FDT method is able to detect C. perfringens at higher levels than the conventional petri plate method (P<0.001) and it also proved to be an effective method to detect differences in C. perfringens counts from the intestines of chickens fed different diet.
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