Source: LOUISIANA STATE UNIVERSITY submitted to NRP
NUTRITIONAL REQUIREMENTS OF FARMED AMERICAN ALLIGATOR
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
Reporting Frequency
Annual
Accession No.
1021432
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Jul 8, 2020
Project End Date
Oct 31, 2023
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
LOUISIANA STATE UNIVERSITY
202 HIMES HALL
BATON ROUGE,LA 70803-0100
Performing Department
Aquaculture Research Station
Non Technical Summary
Farming of the American alligator has become a significant aquaculture enterprise in Louisiana during the last 30 years. Alligator production is now the second largest aquaculture industry in Louisiana and among the five largest animal-production enterprises in the state. In 2018 Louisiana growers produced 612,610 meters (more than two million feet) of alligator skins with a farm-gate value of more than $102 million. In addition to skins, meat of farmed alligator is sold throughout the United States, and new biomedical compounds obtained from alligator show potential for use in treatment of some diseases. Despite its high value as an aquaculture product, however, little research has been conducted on the nutritional needs of alligator. Lack of information on the basic dietary requirements of the American alligator presents a unique challenge for producers engaged in commercial aquaculture. Feed costs are high; nutritional requirements of alligator have not been determined; and effects of nutrition on growth, health, and product quality are largely unknown. Development of effective ways to improve nutrition and feeding of captive-reared alligator will require substantially more information on nutritional requirements of the species. Better diets can improve alligator husbandry, reduce production cost, enhance environmental quality in production systems, and increase farm profit margins. Because the nutritional requirements of alligator are unknown, commercial feeds are fortified to preclude nutritional deficiencies. Feed mills produce high-protein diets for alligator grow-out that are likely to be over-fortified with both essential and non-essential nutrients to ensure that no deficiencies exist. This approach ensures that nutritional deficiencies are unlikely to occur, but lack of flexibility in diet composition also contributes to high feed cost. Also, water quality in the production environment can be negatively impacted by less than optimal feed conversion. Unutilized protein in feeds could contribute to air quality and water quality problems that can affect growth and animal health under intensive production conditions. A research program initiated in this laboratory in 2009 to develop improved diets and feeding practices for farmed alligator will continue in the project proposed here. Since 2009, research has focused on measuring nutrient availability in a variety of feedstuffs, determining optimal ratios of digestible energy-to-digestible protein in alligator diets, identifying appropriate nutrient/ingredient restrictions for diet formulation (e.g., optimal ratios amongdietary essential amino acids), and creating diet formulations based on these criteria for testing in feeding trials. This four-year project will continue to address these priorities. Specifically, facilities at the LSU Agricultural Center Aquaculture Research Station will be used to determine the quantitative, dietary essential amino acid requirements of American alligator and measure availability for alligator of nutrients (i.e., amino acids, protein, and energy) in selected feed ingredients. The information obtained will be used to improve the ingredient composition of alligator diets, increase the biological value of formulated feeds by improving nutrient balance, decrease waste production by increasing nutrient retention, and reduce feed cost by providing more least-cost formulation options.
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
30237991010100%
Goals / Objectives
The goal of theproject is to develop improved diets for alligator aquaculture to reduce animal production cost and optimize environmental quality in the production environment. Objectives are:(1) determine minimum dietary requirements fordietary essential amino acids, (2) determine digestibility coefficients and amino acid availability coefficients for a range of feedstuffs of potential value in alligator diet formulation; and (3) develop feeding strategies that maximize the economic benefits of improved diet formulations. Results of the research will be used to produce a nutrition database that will allow improved least-cost diet formulation for American alligator. Anticipated research will: • Determine minimum dietary requirements for arginine, histidine, isoleucine, leucine, phenylalanine, threonine,and valine. A project to determine the minimum dietary requirements for lysine and methionineis already in progress. • Continue digestibility trials with plant/animal protein products to expand the database of feedstuff nutrient availability coefficients for improved diet formulation. • Utilize the information obtained to identify biological and economic benefits of improved diet formulations.
Project Methods
Laboratory experiments and practical feeding trials will be used to identify nutritional requirements of captive-reared alligators in order to create diet formulations that optimize animal growth, product quality, and feed cost. Nutrition experiments will be conducted in tanks under highly controlled laboratory conditions and under simulated commercial-production conditions. The data collected will be subjected to statistical testing with standard methods, including analysis of variance and regression.Results will be used to make recommendations concerning proper nutrition and feeding of American alligator to optimize benefits to producers.Recommendations will be disseminated through presentations, consultations with businesspeople, extension publications, scientific articles, trade publications, and other appropriate outlets. Success of the project will be measured by the deliverables produced and recommendations adopted.

Progress 07/08/20 to 09/30/20

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 publication of research results;submission of researchreports to the Louisiana Department of Wildlife and Fisheries, the agency involved in regulation of the farm-raised alligator industry;and 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 oftheir 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 alligator industry stakeholders in a peer-reviewed journal article,written reportsto the Louisiana Department of Wildlife & Fisheries, and in consultations with feed manufacturers and other interested businesspeople. What do you plan to do during the next reporting period to accomplish the goals? Research will continue during the next reporting period to systematically address the objectives identified under "Major Goals of the Project".

Impacts
What was accomplished under these goals? Results of research described here will be used to optimize the ingredient composition and nutrient profile of compounded diets for farm-raised American alligator to improve feedconversion efficiency, shorten production time, increase product quality and minimize feed-related production cost. ♦ Preliminary estimates of theminimum requirements for lysine and methionine in formulated alligator feeds were recently completed. Lysineand 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.Diets used in both lysine and methionine feeding trials were formulated with menhaden fish meal (> 55% of diet weight), powdered cellulose, amino acid premix composed of dietary essential and non-essential amino acids formulated to match the composition of fish meal, gelatin, menhaden fish oil, vegetable oil, and a commercial vitamin and mineral premix used in manufactured alligator feeds.Crystalline lysine or methionine were supplemented as needed to achieve desired concentrations in each test diet.In these trials, as we have observed in other types of alligator feeding trials, there was high variability in growth responses among some individuals within each of the treatment groups, but statistically significant differences in growth were observed.Under the conditions of thesestudiesthe dietary lysine requirement of hatchling American alligator was estimated to be 3.57% of the diet (35.7 g/kg dry diet or 87.1 g/kg dietary protein) when fed a 41% crude protein diet containing predominantly menhaden fish meal. The dietary methionine requirement of hatchling alligator was estimated to be approximately 1.27% of the diet (12.7 g/kg dry diet or 28.9 g/kg dietary protein) when fed a 44% crude protein diet containing predominantly menhaden fish meal. A subsequent feeding trial is underway to refine the estimated lysine requirement, after which a similar trial will be conducted to refine the methionine requirement. Until these experiments are completed, a minimum lysine content of 3.6% of diet and minimum methionine content of 1.3% of diet should be recommended for compounded alligator feeds. ♦ Feeding trials and laboratory analyses to measure availability of dietary essential and nonessential amino acids in feedstuffs is continuing.Amino acid availability coefficients (AAAC) are used in diet formulation to improve nutrient balance and avoid deficiencies of dietary-essential amino acids (i.e., those amino acids that must be consumed in the diet because they cannot be synthesized by the Americanalligator). AAAC information is needed for a variety of ingredients to optimize the benefits of least-cost feed formulation, which combines feedstuffs of known nutritional value for a target species to produce an effective diet at lowest cost. Feeding trials were completed in 2020 with porcine blood meal, porcine meat and bone meal, poultry by-product meal, and soybean meal. A new round of feeding trials is underway testing soybean protein isolate, feather meal, and two sources of poultry blood meal.

Publications

  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Reigh, R.C., and M.B. Williams. 2020. Effects of relative humidity and elevated oxygen concentrations on egg-hatching success of American alligator, Alligator mississippiensis. Journal of the World Aquaculture Society 51(4): 982-989. (doi.org/10.1111/jwas.12719)