Robert B. McGeachin

Response of Young Channel Catfish to Diets Containing Purified Fatty Acids

Abstract Nine-gram channel catfish Ictalurus punctatus fed 10 weeks on diets containing ethyl esters of stearic, oleic, linoleic, and linolenic acids did not demonstrate a strong requirement for linolenic-family fatty acids. Growth was inhibited when diets contained 1% or 2% linolenic acid (by weight) but no oleic or linoleic acids. If channel catfish require dietary linolenic acid, it is at a concentration below 1%. The previous view that poor growth of channel catfish on diets supplemented with vegetable oils was due to high levels of linoleic acid appears to have been incorrect. Soybean oil, and other vegetable oils, contain several percent linolenic acid. Growth depression may occur when such oils are utilized at levels of 5 to 10% of the diet. Proximate analyses revealed that fish on all diets had similar body compositions of lipid, protein, and moisture. Among the fatty acids, dietary linoleic and linolenic acid were stored and fish became depleted in those acids when they were excluded from the die...

Growth of Tilapia nilotica in ponds with differing histories of organic fertilization.

Abstract A series of six 0.04 ha ponds that had received varying rates of organic fertilization during 1976 and 1977 were each stocked with 200 Tilapia nilotica for a 3.5 month period during the 1978 growing season. Slotted feeding floors were placed over five of the six ponds and two growing-finishing hogs were placed on each feeding floor. The sixth pond received neither manure nor supplemental feed. Growth of T. nilotica was most rapid in ponds that had a history of relatively high manuring rates. Condition factors paralleled fish growth. Survival was 75% or more in each of the ponds with no apparent correlation between percent survival and history of manuring. Water quality was similar and acceptable for tilapia in each of the six ponds. The data indicated that a stocking rate of 50 hogs/ha can result in high fish yields; and that the history of a ponds experimental use influences subsequent experimental results.

Effect of feeding high levels of androgens on the sex ratio of Oreochromis aureus

Abstract An experiment in which Oreochromis aureus fry were fed ethynyltestosterone (ET) at levels of 60, 90, 120, and 240 mg/kg of feed for 22 days at 27 to 32°C produced 100% male fish. Feeding methyltestosterone (MT) at levels of 60, 90, and 120 mg/kg of feed produced 96–99% males. Accidental overdosing of O. aureus fry with ET or MT (to the extent of 300% of recommended doses) should not hamper practical-scale production of monosex males.

Growth, Food Conversion and Survival of Fingerling Tilapia aurea Fed Differing Levels of Dietary Beef Tallow

Abstract Tilapia aurea fingerlings offered isonitrogenous (32% protein), isocaloric (3600 kcal/kg) semipurified diets for 12 weeks grew significantly larger (P < 0.05) on a 12% beef tallow diet than on a fat-free diet. No significant growth differences were found between the above diets and others which contained 2, 4, 6, 8, 10 or 14% beef tallow. Feed conversion ratio patterns (g dry feed offered/g weight gain) were similar to those for growth. Best food conversion (1.9) occurred in fish fed 12% beef tallow, while poorest (2.8) occurred in fish fed the fat-free diet. Survival was greater than 90% in all treatments, with most losses attributable to escapement. The results of this experiment indicate that beef tallow is a poor dietary lipid source for T. aurea. The generally poor growth may have been due to the relatively low levels of polyunsaturated fatty acids available in the diets.

Collaborating with Students to Develop an Advertising Campaign

Abstract The Texas A&M University Libraries undertook a collaborative project with the local American Advertising Federation (AAF) undergraduate student chapter to develop a marketing campaign to advertise the availability of 30,000 netLibrary electronic books. The promotional campaign resulted in the creation of approximately 200 new user accounts and 3,800 e-book circulations within the first two weeks. The campaign of screensaver ads and posters that were developed are still in use for ongoing promotion of the netLibrary e-books. The AAF students benefited from having an ad campaign to include in their personal portfolios and the Libraries gained a creative and undergraduate student-focused advertising campaign.

Preservation of the Texas Agricultural Experiment Station Bulletin in the Digital Repository

To assist agricultural librarians in their new role as digital preservation and distribution specialists, this article documents the basic procedures for scanning and digitizing print agricultural serial publications and submitting them to a DSpace digital repository, through a case study of a project at Texas A&M University Libraries to digitize Texas Agricultural Experiment Station Bulletins. It is hoped that a dispersed network of similar agricultural materials in all the various land grant university digital repositories could be crawled to harvest the metadata records and make them accessible in a central user-friendly digital library for agriculture.

Manuring Rates for Production of Blue Tilapia in Simulated Sewage Lagoons Receiving Laying Hen Waste

Abstract All-male blue tilapia (Tilapia aurea) were stocked at 50 fish per pool in 7-m² plastic wading pools which received direct input of laying hen manure at the rates of 0, 35, 70, or 140 kg dry weight per hectare per day during 1978 and 70, 140, 210, or 280 kg dry weight per hectare per day during 1979. On the basis of growth and survival of blue tilapia and of water quality data we suggest that the manuring rate in summer should be between 70 and 140 kg per hectare per day, depending on the alkalinity of the water.

Automating the importation of a historic scientific serial into a digital repository

Purpose – The purpose of this paper is to describe the transition of a collection in Texas A&M Universitys institutional repository from single item submission to batch importation as a primary method of ingest. This transition was made possible with assistance and technical work on behalf of the library.Design/methodology/approach – The digital initiatives staff examined the workflow of the collections manager and submitters. A process was created to produce the necessary data structures for batch import from resources that were already being generated by the collection workflow.Findings – It was found that batch importing assistance provided by the library improved the collections growth rate and efficiency without interrupting the workflow of the collection management team.Practical implications – This paper demonstrates the benefit of libraries and other institutional repository hosts offering batch‐loading assistance to managers of large repository collections.Originality/value – This paper should...

The feasibility of using document management software in the scholar's workstation

Abstract A study of the time to locate, acquire, and process articles for storage in a personal collection from conventional paper or electronic sources was conducted. Traditional paper methods of acquiring, indexing, and storing documents, it was found, take twice as long as electronic methods.

Adjusting Feeding Levels in Tank Experiments

Abstract Differences in channel catfish fingerling growth rate were evaluated in triplicate aquaria fed at either 3% or 4% of body weight daily with feeding rate adjustments being made on the basis of (1) weight of the fish in each tank within a treatment, (2) mean weight of all replicates within a treatment, (3) weight of the slowest growing fish within a treatment and (4) weight of the most rapidly growing fish within a treatment. Significant differences between feeding rates were not elaborated over an 11 week feeding trial when the first and third feeding rate adjustment techniques were employed. The first method, utilizing individual tank weights for feeding rate adjustment, is the most common one utilized in feeding trials. Our recommendation is that it be retained as the standard technique. The low sensitivity of the technique reinforces the view that significant differences, when detected, are biologically important and not an artifact of experimental design.