Progress 04/29/15 to 03/31/19
Outputs
Target Audience: Target audiences of the project are members of the scientific community, alligator feed manufacturers, and farmers involved in production of American alligator for skins and meat. Outreach to these audiences was achieved through presentations at scientific meetings and commodity-organization meetings of the Louisiana alligator industry, meetings with personnel of the Louisiana Department of Wildlife and Fisheries involved in regulation of the farm-raised alligator industry, and in-person consultations with feed manufacturers and other interested businesspeople. Several undergraduate students and one graduate student have gained knowledge of aquacultural production practices for American alligator as a result of their work on this project. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? The project provided training opportunities for several undergraduate students and one graduate student in the LSU School of Renewable Natural Resources who assisted the project director and a research associate in conducting the research. These students gained knowledge of, and experience with, laboratory analytical procedures, proper animal husbandry practices, and the development of aquacultural production practices for captive-reared alligator as a result of their work on this project. How have the results been disseminated to communities of interest? During this final reporting period (October 2018 to March 2019), results were disseminated to scientists and the general public intwo written reports to the Louisiana Department of Wildlife & Fisheries, and in oneoral report to alligator producers at a meeting of the LouisianaAlligator Farmers and Ranchers Association. Publications derived from research conducted during the full, four-year term of this project have been cited in previous progress reports. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
• The first phase of a study to determine the effects of environmental oxygen concentrations during egg incubation on umbilical scarring of alligators raised to market size was completed. An umbilical scar reduces the market value of an alligator skin and anecdotal evidence suggests that hyperoxic incubation conditions might reduce the incidence of this condition. Three-hundred alligator eggs (10 clutches of 30 eggs each) were incubated (88 F, 90%+ relative humidity) in one of three atmospheric oxygen concentrations: 21% oxygen (approximating ambient air), 25% oxygen, or 28% oxygen. When hatchlings emerged, the umbilical area (site of yolk sac attachment) was measured and photographed. Hatchlings were tagged with an ID chip for tracking and transferred to a commercial farm for grow-out to market size. Results of the incubation trial indicated no significant differences in egg-hatching rates among the three oxygen treatments. Since transfer to the farm, the animals have been weighed and measured twice, in the fall of 2018 and spring of 2019. Final measurements of body weight and body length, and umbilical-scar grading for each tagged alligator will be available at the end of the grow-out period, likely in spring 2020. • Lysine and methionine are typically two of the most growth-limiting amino acids in compounded animal feeds due to their relatively low concentrations in feedstuffs relative to the quantitative dietary requirements of most animals for these essential nutrients. Feeding trials to estimate minimum dietary requirements of alligator for lysine and methionine were recently completed. Data analysis is in progress. • "Double-scale" is a condition observed among farmed alligators in which scales on the belly and along the flanks of affected animals do not shed properly as the animal grows. This condition creates problems during the tanning process which decreases the quality and value of the finished leather. Because the cause of the condition is unknown, laboratory analyses were conducted to compare the amino acid composition of normal alligator scale, skin, and underlying muscle to that of scale, skin, and muscle from animals with double-scale to determine if amino acid composition might be a factor associated with this abnormality. Results showed no significant differences in amino acid composition of scales, skin, or muscle taken from alligators with normal-scale or double-scale condition, indicating that amino acid composition of these tissues may not be a factor affecting the development of this condition. • Feeding trials and laboratory analyses to measure apparent digestibility of protein and energy, and availability of dietary essential and nonessential amino acids in feedstuffs, is continuing. Feeding trials with porcine meat and bone meal, poultry feather meal, and poultry blood meal have been completed. Laboratory analyses of feeds and fecal samples are in progress. Feeding trials with porcine blood meal, poultry by-product meal, and soybean meal are in progress. Results of the alligator research described here will be used to improve egg-incubation practices to maximize egg-hatching success, and to optimize the ingredient composition and nutrient profile of compounded alligator diets to improve feed conversion efficiency, shorten production time, increase product quality and minimize feed-related production cost.
Publications
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Progress 10/01/17 to 09/30/18
Outputs
Target Audience:Target audiences of the project are members of the scientific community, alligator feed manufacturers, and farmers involved in production of American alligator for skins and meat. Outreach to these audiences was achieved through presentations at scientific meetings and commodity-organization meetings of the Louisiana alligator industry, meetings with personnel of the Louisiana Department of Wildlife and Fisheries involved in regulation of the farm-raised alligator industry, and in-person consultations with feed manufacturers and other interested businesspeople. Several undergraduate students and one graduate student have gained knowledge of aquacultural production practices for American alligator as a result of their work on this project. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The project provided training opportunities for several undergraduate students and one graduate student in the LSU School of Renewable Natural Resources who assisted the project director and a research associate in conducting the research. These students gained knowledge of, and experience with, laboratory analytical procedures, proper animal husbandry practices, and the development of aquacultural production practices for captive-reared alligator as a result of their work on this project. How have the results been disseminated to communities of interest?Results were disseminated to scientists and the general public in two refereed journal articles and one published abstract, in written reports to the Louisiana Department of Wildlife & Fisheries, and in oral reports to alligator producers at meetings of the Louisiana Alligator Advisory Council and the Louisiana Alligator Farmers and Ranchers Association. What do you plan to do during the next reporting period to accomplish the goals?In 2019 we will (1) complete studiesto quantify minimum dietary requirements forlysine and methionine;(2) conduct digestibility trials to determine amino acid availability of poultry blood meal; and (3) continueresearch to identify causes of skin-quality problems among farmed alligators.
Impacts
What was accomplished under these goals?
• Husbandry practices that could negatively affect skin quality are a primary concern of alligator producers. Among these are potential effects of diet and environment on animal health. A 10-month feeding trial was conducted to determine effects on alligator growth and health of removing fat-soluble vitamin supplements from commercially manufactured diets. Results showed no difference among animals, as determined by necropsy or histopathological examination, indicating that removal of fat-soluble vitamin supplements from the standard (control) diet did not produce visible health effects after 10 months of feeding. • A laboratory experiment was conducted to identify acute effects of airborne ammonia, often present in production houses at variable concentrations, on the health of juvenile alligators. All animals were subjected to necropsy and histopathological examination after treatment to determine effects of ammonia on selected organs and tissues. Necropsies and histopathological examinations by veterinary pathologists found no differences among treatment groups, indicating that exposure to atmospheric ammonia for 48 hours at concentrations up to 200 ppm produced no observable effect on alligator tissues. • A study is in progress to determine the effects of environmental oxygen concentrations during egg incubation on umbilical scarring of alligators raised to market size. An umbilical scar reduces the market value of an alligator skin and anecdotal evidence suggests that hyperoxic incubation conditions might reduce the incidence of this condition. When hatchlings emerged, the umbilical area (site of yolk sac attachment) was measured and photographed. Hatchlings were tagged with an ID chip for tracking and transferred to a commercial farm for grow-out to market size. Results will be available at the end of the grow-out period (late 2019). • Feeding trials to estimate minimum dietary requirements for the essential amino acids lysine and methionine were recently completed. Laboratory analyses of tissue samples are in progress. Results of the alligator research described here will be used to improve egg-incubation practices to maximize egg-hatching success, and to optimize the ingredient composition and nutrient profile of compounded alligator diets to improve feed conversion efficiency, shorten production time, increase product quality and minimize feed-related production cost.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Reigh, R.C., and M.B. Williams. 2018. Plant products in compounded diets are effectively utilized by American alligator, Alligator mississippiensis. Journal of the World Aquaculture Society (doi: 10.1111/jwas.12520).
- Type:
Other
Status:
Published
Year Published:
2018
Citation:
Reigh, R. 2018. AgCenter research aims to boost Louisiana alligator industry. Louisiana Agriculture 61(4): 30-31.
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Progress 10/01/16 to 09/30/17
Outputs
Target Audience:Target audiences of the project are members of the scientific community, alligator feed manufacturers, and farmers involved in production of American alligator for skins and meat. Outreach to these audiences was achieved through presentations at scientific meetings and commodity-organization meetings of the Louisiana alligator industry, meetings with personnel of the Louisiana Department of Wildlife and Fisheries involved in regulation of the farm-raised alligator industry, and in-person consultations with feed manufacturers and other interested businesspeople. Several undergraduate students and one graduate student have gained knowledge of aquacultural production practices for American alligator as a result of their work on this project. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The project provided training opportunities for several undergraduate students and one graduate student in the LSU School of Renewable Natural Resourceswho assisted the project director and a research associate in conducting the research. These students gained knowledge of, and experience with, laboratory analytical procedures, proper animal husbandry practices, and the development of aquacultural production practices for captive-reared alligator as a result of their work on this project. How have the results been disseminated to communities of interest?Results were disseminated to scientists and the general public in two refereed journal articles,in written reports to the Louisiana Department of Wildlife & Fisheries, and in oral reports to alligator producers at meetings of the Louisiana Alligator Advisory Council and the Louisiana Alligator Farmers and Ranchers Association. What do you plan to do during the next reporting period to accomplish the goals?In 2017-2018 we will (1) completealong-term feeding trial to identify effects offat-soluble vitamin deficiencies on alligator health and skin quality; (2)quantify minimum dietary requirements for twodietary essentialamino acids(lysine and methionine);and (3)determinethe effects on alligator health ofexposure toammoniaat a range of atmospheric concentrationssimilar to those found on commercial farms.
Impacts
What was accomplished under these goals?
A preliminary study of the effects of elevated environmental oxygen concentrations on hatching success of alligator eggs showed no significant difference (P > 0.05) in hatch rate (mean, 82 percent) of eggs subjected to concentrations of 24 percent atmospheric oxygen or 28 percent atmospheric oxygen during incubation. Length (mean, 75 cm), weight (mean, 1.2 kg), and girth (mean, 21 cm) of alligators hatched under the two oxygen treatments also did not differ (P > 0.05) after 10 months of growth, suggesting no beneficial effect of hyperoxic incubation conditions on long-term growth. A follow-up experiment to determine the effects of relative humidity (80 percent vs. 93 percent) and elevated oxygen concentration (21 percent vs. 28 percent) on hatching success showed no difference (P > 0.05) in hatch rate (mean, 83 percent) of eggs incubated at 93 percent relative humidity in either the hyperoxic atmosphere or at ambient (21 percent) oxygen concentration. Hatching success of eggs incubated at 80 percent relative humidity was less than 2 percent for both oxygen treatments combined. Results indicated that 80 percent relative humidity reduced egg hatching success to nearly zero, regardless of atmospheric oxygen concentration, while 93 percent relative humidity produced good hatching success. Elevated atmospheric oxygen concentration (7 percent above ambient) had no effect on egg-hatching success under the conditions of this study. A 10-month feeding trial is in progress to determine effects on alligator growth and health of removing fat-soluble vitamin (A, D, and E) supplements from commercially manufactured diets. Results will provide information on vitamin deficiency symptoms in farm-raised alligators which is currently unavailable. Results of these studies will be used to improve incubation practices to maximize egg hatching success and to optimize the ingredient composition and nutrient profile of compounded alligator diets to improve feed conversion efficiency, shorten production time, increase product quality, and minimize feed-related production costs.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
DiGeronimo, P.M., N. Di Girolamo, N.A. Crossland, F. Del Piero, R.C. Reigh, and J.G. Nevarez. 2017. Effects of plant protein diets on the health of farmed American alligator (Alligator mississippiensis). Journal of Zoo and Wildlife Medicine 48(1): 131135.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Nickum, M.J., M. Masser, R. Reigh, and J.G. Nickum. 2017. Alligator (Alligator mississippiensis) aquaculture in the United States. Reviews in Fisheries Science and Aquaculture, DOI: 10.1080/23308249.2017.1355350
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Progress 10/01/15 to 09/30/16
Outputs
Target Audience:Target audiences of the project are members of the scientific community, alligator feed manufacturers, and farmers involved in production of American alligator for skins and meat. Outreach to these audiences was achieved through presentations at scientific meetings and commodity-organization meetings of the Louisiana alligator industry, meetings with personnel of the Louisiana Department of Wildlife and Fisheries involved in regulation of the farm-raised alligator industry, and in-person consultations with feed manufacturers and other interested businesspeople. Several undergraduate students have gained knowledge of aquacultural production practices for American alligator as a result of their work on this project. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The project provided training opportunities for several undergraduate students in the LSU School of Renewable Natural Resources and the School of the Coast & Environment who assisted the project director and a research associate in conducting the research. These students gained knowledge of, and experience with, laboratory analytical procedures, proper animal husbandry practices, and the development of aquacultural production practices for captive-reared alligator as a result of their work on this project. How have the results been disseminated to communities of interest?Results were disseminated to scientists and the general public in three refereed journal articles, a conference abstract, and an article in a popular aquaculture trade magazine.Results also were disseminated in written reports to the Louisiana Department of Wildlife & Fisheries and in oral reports to alligator producers at meetings of the Louisiana Alligator Advisory Council and the Louisiana Alligator Farmers and Ranchers Association. What do you plan to do during the next reporting period to accomplish the goals?In2016-2017we will (1) continuelong-term feeding trials to identify optimum levels of plant productsfor alligator grow-out feeds; (2)begin quantifying minimum dietary requirements for selected amino acids,starting with lysine and methionine requirements; and (3) evaluate the effects of normal and elevated oxygen concentrationsduring egg incubation on alligator growth during the first year post-hatch.
Impacts
What was accomplished under these goals?
Costs of compounded diets containing fish meal as a primary protein source can be expected to rise as fish meal prices increase in response to static supply and growing demand. Alternatives to fish meal are needed to reduce production costs in many aquacultural enterprises. Some plant proteins are potential replacements for fish meal because of their amino acid composition, lower cost and wide availability. However, knowledge of nutrient availability of feedstuffs is needed to use new ingredients most effectively to improve diets and reduce costs in alligator aquaculture. Research in 2015-2016 included measurements of protein digestibility; energy digestibility; and the availability of amino acids in poultry blood meal, corn gluten meal, cottonseed meal, rice bran, grain sorghum, and wheat middlings. Results showed wide variation in the apparent availability of dietary essential amino acids among the ingredients tested: i.e., arginine, 40-76%; histidine, 14-100%; isoleucine, 12-76%; leucine, 38-83%; lysine, 46-66%; methionine, 43-84%; phenylalanine, 57-100%; threonine, 10-69%; and valine, 11-86% apparent availability. Corn gluten and poultry blood meal had the highest average dietary essential amino acid availability, 72% and 61%, respectively, among the ingredients tested. A feeding trial, begun in fall 2015, to determine the effects of stocking density and commercially manufactured diets containing different levels of fish meal on growthof large (1.5-m) alligator was completed. Results indicated no statistically significant effects of treatment -- high vs.low stocking density or fish meal content of the diet -- on alligator growth. Results of these studies will be used to optimize the ingredient composition and nutrient profile of compounded alligator diets which could improve feed conversion efficiency, shorten production time, increase product quality, and minimize feed-related production cost.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Patterson, J., C. Ohs, P. OMalley, A. Palau, L. DAbramo, R. Reigh, and C. Green. 2016. Feeding larval Gulf killifish: Total replacement of Artemia nauplii and co-feeding from hatch. North American Journal of Aquaculture 78(4): 396-404. (doi: 10.1080/15222055.2016.1201555)
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Reigh, R.C., and M.B. Williams. 2016. Feed intake and length-weight relationship of captive American alligator fed a compounded diet. World Aquaculture 47(1): 63-65.
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2017
Citation:
Di Girolamo, N., N. Crossland, F. Del Piero, R. Reigh, and J. Nevarez. 2017. Effects of plant protein diets on the health of farmed American alligators (Alligator mississippiensis). Journal of Zoo and Wildlife Medicine (In press).
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Reigh, R.C., and M.B. Williams. 2016. Plant products in compounded diets are effectively utilized by American alligator Alligator mississippiensis. Page 663 in: Abstracts of Aquaculture 2016, Las Vegas, Nevada, February 2016.
- Type:
Other
Status:
Published
Year Published:
2016
Citation:
Bullard, H.T., R. Reigh, and M. Williams. 2016. Uptake of copper by American alligators exposed to pressure-treated wood products. Aquaculture Magazine 42(4): 12-15.
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Progress 04/29/15 to 09/30/15
Outputs
Target Audience: Target audiences of the project are members of the scientific community, alligator feed manufacturers, and farmers involved in production of American alligator for skins and meat. Outreach to these audiences was achieved through presentations at scientific meetings and commodity-organization meetings of the Louisiana alligator industry, meetings with personnel of the Louisiana Department of Wildlife and Fisheries involved in regulation of the farm-raised alligator industry, and in-person consultations with feed manufacturers and other interested businesspeople. Several undergraduate students have gained knowledge of aquacultural production practices for American alligator as a result of their work on this project. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? The project provided training opportunities forseveral undergraduate students in theLSU School of Renewable Natural Resources and the School of the Coast & Environmentwho assisted the project director and a research associate in conducting the research. These students gained knowledge of, and experience with, laboratory analytical procedures, proper animal husbandry practices, and the development of aquacultural production practices for captive-reared alligator as a result of their work on this project. How have the results been disseminated to communities of interest?Results were disseminated to scientists and the general public in aprofessional-society magazine article (submitted),twoprint interviews published innational online magazines, and in a newspaperarticle in the local area. Results also were disseminated inwritten reports to the Louisiana Department of Wildlife & Fisheries and inoral reports toalligator producers at meetings of theLouisiana Alligator Advisory Council and the Louisiana Alligator Farmers and Ranchers Association. What do you plan to do during the next reporting period to accomplish the goals? Work will continueon measurement ofnutrient digestibility in common feed ingredients and determination of optimum fish meal concentrations in diets of large alligators. Longer-term goals include conducting experiments to determineselected amino acidrequirements ofcaptive-reared alligator.
Impacts
What was accomplished under these goals?
Results of nutrition research with American alligator were used to develop cost-effective improvements in diet formulations to facilitate sustainable production of this species and identify additional research needed to promote efficient production of alligator as an aquaculture product. Information on the use of plant proteins to improve compounded diets for American alligator was disseminated to scientists, aquacultural producers, feed manufacturers and other interested stakeholders in a variety of outreach efforts. Costs of compounded diets containing fish meal as a primary protein source can be expected to rise as fish meal prices increase in response to static supply and growing demand. Alternatives to fish meal are needed to reduce production costs in many aquacultural enterprises. Some plant proteins are potential replacements for fish meal because of their amino acid composition, lower cost and wide availability. However, knowledge of nutrient availability of feedstuffs is needed to use new ingredients most effectively to improve diets and reduce costs in alligator aquaculture. Research with American alligator included measurements of protein digestibility, energy digestibility, and the availability of amino acids in poultry blood meal, chicken-protein concentrate, corn gluten meal, cottonseed meal, rice bran, grain sorghum, and wheat middlings. Data collection/analysis and evaluation of these feedstuffsis currently in progress. A laboratory experiment done a few years ago on the effects of dietary protein on alligator weight, length, chest girth, and ammonia concentrations in water and air of the production system indicated that a diet containing 45 percent digestible protein was optimal. Results suggested that equivalent animal growth and equivalent (or better) water quality in production systems can be obtained with a lower-protein diet than the current industry-standard formulation. In a follow-up laboratory study, information on digestible protein, digestible energy, and available amino acids in a group of previously evaluatedfeedstuffs was used to formulate a series of plant-based "ideal protein" diets based on the amino acid composition of alligator whole-body. These diets were fed to hatchling alligators for 7.5 months to determine effects on body weight gain, body length and chest girth (an index of belly skin width). Results indicated that a diet containing 45 percent digestible protein (DP) and 37.7 kilojoules (9 kcal) of digestible energy per gram of DP produced gains in all parameters of interest that were equivalent to those obtained with a commercially manufactured control diet. This suggested that alligators are capable of effectively utilizing a diet containing more than 80 percent plant products; and when such a diet is nutritionally balanced, growth performance can be comparable to that obtained with a diet of animal protein. In 2014-2015 research, a commercially manufactured version of this plant-based diet was tested in a production-scale feeding trial. One-hundred-ninety-two alligators were stocked as hatchlings and raised under simulated production conditions for 10 months. Alligators received one of three dietary treatments: A 56% crude protein (CP) commercial diet fed for 3 months, followed by a 50% CP commercial diet fed for 7 months; the 56% CP diet fed for 3 months, followed by the 45% DP plant-based diet fed for 7 months; or the 45% DP diet fed for 10 months. Results indicated that mean length and weight (L/W) of alligators fed only the plant-based diet was lower than L/W of animals fed the two commercial (animal-based) diets but L/W of alligators fedthe animal-based diet (3 months) followed by the plant-based diet (7 months) was not different from L/W of alligators in the other two treatment groups, suggesting that protein content of the diet fed during the first 3 months was a primary factor affecting growth. The range of growth responses among animals in all three treatment groups showed that some better-performing individuals in the plant-diet treatment also grew as large as animals in either of the other treatment groups. Results indicated that American alligator can effectively utilize plant products in a compounded diet, and additional research on the use of selected plant products in alligator feeds is warranted. A new feeding trial, begun in fall 2015, is testing the effects of stocking density and commercially manufactured diets containing different levels of fish meal on growth and body composition of 1.5-m alligators, with the goal of increasing production oflarge animalsdesired by a growing segment of the market. This trial will terminate in September 2016. Results of these studies will be used to optimize the ingredient composition and nutrient profile of compounded alligator diets which could improve feed conversion efficiency, shorten production time, increase product quality and minimize feed-related production cost.
Publications
- Type:
Other
Status:
Submitted
Year Published:
2015
Citation:
Feed Intake and Length-Weight Relationship of Captive American Alligator (Alligator mississippiensis) Fed a Compounded Diet. World Aquaculture (submitted November 2015).
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