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Determining the Dietary Tryptophan Requirement of Juvenile Red Drum
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The Dietary Tryptophan Requirement of Juvenile Red Drum. (May 2015)
Emily Pewitt
Department of Wildlife and Fisheries Sciences
Texas A&M University
Research Advisor: Dr. Delbert M. Gatlin III
Department of Wildlife and Fisheries Sciences
The red drum, Sciaenops ocellatus, is cultured in the United States for both stock enhancement and food production. Ongoing studies in this laboratory are quantifying optimum dietary levels of indispensable and dispensable amino acids of red drum in order to compile a complete set of nutritional requirements. The present study was conducted to determine the optimum dietary tryptophan requirement of red drum. Groups of twelve red drum fingerlings, of initial average weight of 1.5- 2.5 g each were placed into each of 28, 38-L aquaria containing brackish water (7ppt) prepared from well water and a mixture of stock salt and commercial synthetic seawater. Seven semi-purified diets composed of red drum muscle and crystalline amino acids were supplemented with incremental levels of tryptophan. Each diet was given to triplicate groups of fish which were weighed every week to observe health and growth as influenced by dietary tryptophan. Water quality samples were also observed multiple times per week. At the end of the 39-day feeding period, the optimal tryptophan requirement of red drum was estimated based on weight gain, feed efficiency and protein conversion efficiency. Red drum fed the basal diet without adequate tryptophan exhibited significantly (P< 0.05) reduced weight gain, feed efficiency and survival compared to fish fed the other diets. However, no other specific signs of deficiency were observed. All of the diets supplemented with tryptophan from 0.25 to 0.75% supported similar growth performance. Based on these data, the minimum dietary tryptophan requirement of red drum was determined to be 0.25% of dry diet. This information can be used in formulating diets for red drum to ensure adequate levels of tryptophan are provided
Evaluating the Effects of Fermented and Non-Fermented Cottonseed Flour on Growth Performance of Juvenile Red Drum Sciaenops Ocellatus and Hybrid Striped Bass Morone Chrysops �� M. Saxatilis
Get PDFThere continues to be a pressing need to develop alternative protein feedstuffs to reduce dependence on fishmeal (FM) and other costly ingredients and thereby increase the sustainability and potential expansion of global aquaculture. In this study, three feeding trials were conducted to evaluate the effects of substituting FM, soybean meal (SBM), or a combination of both with a premium cottonseed flour (CSF) included at incremental levels in the diets of red drum and hybrid striped bass. Feeding trial 1 utilized juvenile red drum, and the remaining two trials were conducted with juvenile hybrid striped bass. Each trial was conducted in 38-L aquaria operated as a recirculating system, and each experimental diet was fed to triplicate groups of juvenile fish for 8 weeks. Red drum in trial 1 were able to readily consume diets in which up to 50% of FM protein was replaced with CSF without observing an appreciable decline in weight gain, feed efficiency or survival. Replacing 75% of FM protein with two different CSF products did result in reduced weight gain and feed efficiency of red drum. Hybrid striped bass in trial 2 were able to readily consume diets in which up to 50% of SBM protein was replaced with either fermented or non-fermented CSF without observing an appreciable decline in weight gain, feed efficiency or survival, while 75% replacement produced lower responses, and replacing 37.5% of protein from both FM and SBM resulted in the lowest responses. Hybrid striped bass in trial 3 were able to readily consume diets in which 30% of SBM and FM protein was replaced with either fermented or non-fermented CSF without observing an appreciable decline in weight gain, feed efficiency or survival. Fermentation of CSF did not substantially improve its nutritional value to hybrid striped bass. Additionally, hybrid striped bass were more sensitive to the inclusion of CSF when substituted for protein from both SBM and FM rather than SBM alone. In conclusion, diets for red drum and hybrid striped bass could conservatively include one third of its protein provided by CSF without negatively affecting their growth performance or body composition
The Association of Virulent Vibrio Spp. Bacteria on Gafftopsail and Hardhead Catfish in Galveston Bay
Get PDFVibrio vulnificus (Vv) and V. parahaemolyticus (Vp) are gram negative, halophilic bacteria that occur naturally in estuarine waters of Galveston Bay. Both bacteria have the potential to cause infections in humans either via consumption or direct contact. Finfish are a potential vector for these bacteria. Previous work by Brinkmeyer determined that these bacteria are present on the benthic dwelling catfish, Ariopsis felis and Bagre marinus, using a conventional microbial method. The present work focused on using Quantitative Polymerase Chain Reaction (QPCR) and Terminal Restriction Fragment Length Polymorphism (T-RFLP) to not only determine presence of these bacteria, but also to quantify them and look at community structure.
QPCR was able to detect bacteria presence in 34 percent, 31.6 percent, and 0 percent for V.vulnificus, V.parahaemolyticus. thermolabile hemolysin (tlh) and thermostable direct hemolysin (tdh) genes, respectively. Statistical analysis of the QPCR results found that there was no significant difference between the length of fish, location of catch or species of fish in relation to the abundance of bacteria.
T-RFLP was able to detect the presence of bacteria in approximately 70 percent of the samples surveyed. Bands produced from T-RFLP were able to be grouped into five different ranges. The most frequently occurring band fell in the range of 213-219 base pairs, and the most common number of bands per sample was 1 band.
This study found that both QPCR and T-RFLP were better assays than conventional microbial methods for detecting the presence of V. vulnificus and V. parahaemolyticus on catfish fins. QPCR proved to be the most rapid detection method. Based on this study, it was determined that these Vibrio spp. bacteria have some type of relationship with A. felis and B. marinus. This information may be useful to the medical community for determining when there is a greater risk of infection via catfish puncture wounds
Evaluating the Effect of Prebiotics and Probiotics on Rotifer and Juvenile Red Drum (Sciaenops ocellatus) Production
Get PDFCommercially produced probiotics and prebiotics show potential to enhance growth performance and disease resistance of various animals but have not been evaluated as enrichments in live foods for larval fish. Therefore, four separate trials were conducted to evaluate changes in the production and microbial composition of rotifers (Branchionus plicatilis) exposed to the probiotics Bactocell™ and Aquablend™ and prebiotics Grobiotic®-A, and SILOhealth 108P added to the water during 4-day cultures compared to the control with no supplement. Grobiotic®-A showed potential to increase rotifer production while Bactocell™ decreased production. Denaturing gel gradient electrophoresis (DGGE) analysis demonstrated rotifers cultured with aforementioned additives except SILOhealth 108P altered microbiota composition compared to the control. Bactocell™, a commercial probiotic consisting of Pediococcus acidilactici, has shown benefits to immunomodulation, nutrient digestion, and feed utilization in shrimp but has not been evaluated in fish. Therefore, a feeding trial was conducted with juvenile red drum (Sciaenops ocellatus) fed diets with graded concentrations of Bactocell™ (0, 0.05, 0.1, 0.2, 0.4, and 0.8% of dry weight) for 8 weeks. The diets were formulated primarily from soybean protein sources with low amounts of menhaden fishmeal to contain 44% crude protein and 10% lipid. Each diet was fed to fish in quadruplicate 38-L aquaria for 8 weeks. Digesta from red drum was obtained at the end of weeks 4 and 8 to characterize microbiota by DGGE analysis. Red drum fed experimental diets grew rapidly and achieved a 1,300% increase in initial body weight after 8 weeks; however, no significant (P < 0.05) differences in weight gain, feed efficiency, or survival could be attributed to different concentrations of Bactocell™. After 8 weeks of feeding, DGGE analysis iii showed that Bactocell™ altered the microbiota of red drum digesta compared to fish fed the basal diet. The prebiotics and probiotics tested except SILOhealth 108P altered the microbiota of rotifers after a 4-day cycle. Bactocell™ altered the digesta microbiota of red drum but did not improve fish growth or survival. Additional investigations under harsh environmental conditions in which immunological responses and/or disease resistance are assessed may be required to demonstrate potential benefits of dietary Bactocell™ supplementation
Mitigation of Prymnesium parvum Blooms by Clipper Herbicide
Get PDFThe harmful algal species Prymnesium parvum, also known as golden algae, is toxic to many forms of aquatic life. When it blooms it kills fish and other aquatic organisms and can have long-lasting impacts on the ecosystem where it blooms. Many forms of treatments are employed to control P. parvum, including chemical methods. Flumioxazin, the active ingredient of Clipper herbicide, hasbeen effective at controlling P. parvum in small-scale situations. A concentration gradient of Flumioxazin including 50, 100, 200, and 400��g/L was tested in its commercial form of Clipper in a laboratory setting to determine whether it would be effective, considering its supposed inactive and inert ingredients. Varying conditions at the time of application were also examined to aid in decision making processes where Clipper is being considered as a means of control. The conditions examined were season (fall and winter of the southeastern United States) and growth stage (log and stationary) of P. parvum. Through the use of cell counts by light microscopy and chlorophyll-a fluorescence, Clipper was determined to control P. parvum in winter season, but not in fall season, and to be more effective when applied in P. parvum���s log growth phase than in its stationary growth phase. This is likely due to P. parvum having an optimum growing temperature closer to the fall season than the winter season of the southeastern United States and that the growth rate of P. parvum in its stationary phase is already low in comparison to its growth rate in log growth
Distribution and Evolution of Heterodonty in the Ray-finned Fishes (Actinonpterygii)
Get PDFHeterodonty, having multiple different types of teeth in the jaws, is well documented in chondrichthyan and sarcopterygian lineages, but is poorly documented within the Actinopterygii (ray-finned fishes). To further our understanding of actinopterygian dentition, a broad-scale literature review of tooth types across all families of actinopterygian fishes was conducted to (1) summarize the diversity of oral jaw teeth that exists within the group and (2) assess the distribution of heterodonty. Based on a thorough survey of the published literature on actinopterygian fishes, 15 distinct types of oral jaw teeth are recognized and named based on attributes of tooth shape. Heterodonty is widespread within the Actinopterygii and is documented in 20 of the 45 orders ray-finned fishes. The oral jaws of actinopterygiian fishes have 39 distinct forms of heterodonty, which comprise two, three or four different tooth types. The results of ancestral character state reconstruction analyses, conducted in conjunction with a recently published molecular phylogenetic hypothesis for actinopterygian fishes, confirm that heterodonty has evolved multiple times throughout the evolutionary history of the group and suggest that a homodont dentition comprised only of coniform teeth is a plesiomorphic condition for the Actinopterygii. Summaries of oral jaw teeth are provided for 3,000 species of ray-finned fishes, representing 442 families and 45 orders
Evaluation of the Nutritional Value of Seafood By-Product Blends with Red Drum Sciaenops Ocellatus and Hybrid Striped Bass Morone Saxatilis X M.Chysops
Get PDFDiets of many cultured fishes require high inclusion of fishmeal and fish oil.
With the growth of aquaculture worldwide, demand for fishmeal and fish oil has
increased resulting in higher prices of these ingredients due to increased demand but
relatively static supplies. A promising source of alternative protein and lipid is the waste
from seafood processing.
This project evaluated four different types of seafood processing wastes as
potential feed ingredients for the red drum (Sciaenops ocellatus) and hybrid striped bass
(Morone saxatilis x M. chysops). Viscera and skeletal remains from filleted channel
catfish (Ictalurus punctatus), black drum (Pogonias cromis), yellowfin tuna (Thunnus
albacares) and krill (Euphausia superba) were evaluated with red drum and hybrid
striped bass by determining nutrient and energy digestibility. Catfish, black drum, and
tuna waste products were blended with soybean meal in a 40:60 ratio. All diets were
subjected to dry extrusion, and then dried to produce stable ingredients. Diets used for
the digestibility trial were formulated to contain 40% crude protein, 10% lipid and 1%
chromic oxide as a marker, with each ingredient substituted in a reference diet at a 30:70
ratio. The yellowfin tuna fillet waste also was evaluated in a comparative feeding trial
with juvenile red drum. In that trial, experimental diets with the tuna by-product meal
replaced menhaden fishmeal on an equal protein basis at levels of 5, 10, 20, 40 or 60%.
Diets were formulated to contain 40% crude protein and 12% lipid. Juvenile red drum
were fed the various diets for 7 weeks in 38-L aquaria linked as a brackish (6 + 1 ppt) water recirculating system.
Apparent digestibility coefficient (ADC) values for crude protein, crude lipid, and energy from krill and catfish meal were similar for red drum while the black drum meal had decisively lower values. Krill meal had higher ADC values for organic matter and energy than catfish meal and black drum meal in hybrid striped bass. ADC values of crude protein, and crude lipid were similar for krill, catfish, and black drum ingredients.
Based on weight gain and feed efficiency responses in the feeding trial, red drum fed the control diet with only fishmeal significantly outperformed fish fed the tuna-substituted diets. However, no significant differences were observed among fish fed the diets with 5, 10, 20, or 40% tuna substitution. These results suggest that inclusion of seafood processing by-products can be substituted for fishmeal and possibly reduce the price of fish feeds
Re-Evaluation of the Dietary Vitamin D3 Requirement of Modern Broiler Chickens Using Novel Oral Intubation
Get PDFThe studies in this dissertation were conducted to evaluate the response of modern broiler chickens to dietary D 3 and 25-OH-D 3 (25-hydroxycholecalciferol) as well as to establish a marginal vitamin-D-depleted broiler breeder flock to increase the sensitivity of the oral gavage bioassay establish previously in our laboratory.
In the first and second experiments, commercial broiler chickens were fed a diet devoid of D 3 for 17 and 21 d, respectively. The first 9 d of the study served as a depletion period of the maternal stores of D 3 . On d-10 through the end of each trial, birds were offered commercially available sources of vitamin D 3 or 25-OH-D 3 by gavage daily. The basal diets were formulated with sub-optimal levels of calcium and nonphytate phosphorus (0.75 and 0.375% respectively). Experiment 1 results indicated no significant performance differences between dietary supplementation of either vitamin D3 or 25-OH-D3 . However, significant (P<0.05) differences for body weight (BW) and weight gain (WG) between the negative control and treatment groups were observed. For experiment 2, no performance or bone mineralization differences were detected between treatment groups or the negative control. This suggests that maternal stores of D3 in the yolk were sufficient to last the broiler chicks through the duration of the trial.
In the third trial, a commercial breeder flock was marginally depleted of vitamin D in order to run a vitamin D requirement study on the progeny chicks. A negative control response was observed between all treatment groups and suggests that establishing a marginally vitamin-D-deficient breeder flock increases the sensitivity of establishing vitamin D requirements. Furthermore, this experiment estimated the vitamin D3 requirement to be 73 IU/kg of feed based on bone ash. Using industry-type diets as in this trial, the dietary D3 requirement appears to be lower than reported in the NRC (1994).
The last trial evaluated the vitamin D requirement of two modern broiler strains (Cobb-500 and Cobb-700) using the oral gavage intubation assay. Results from this study showed no significant differences in performance parameters, however, main effect differences between strains for all performance and bone mineralization parameters were observed
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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