Marifeed attended the 2015 International Abalone Symposium to meet with customers, present the results of research it had collaborated on and to keep up to date with developments in the industry. Along the way a summary presentation of some Marifeed research, conducted by Rhodes University, was awarded the prize for best oral presentation at the conference.
Rowan Yearsley (right) accepts the prize for Best Oral Presentation at the 9th International Abalone Symposium.
In the development of our new website, we have focused on sharing tips, scientific findings, and interacting with our customers worldwide.
On the go? No access to a computer? No problem, we have set up a mobi site, which will display the same info as the main website, in a format optimised for small mobile screens. The mobi site will automatically display when you view this website on a smartphone.
THE GROWTH OF POST-WEANING ABALONE ON VARIOUS FORMULATED FEEDS FORTIFIED WITH SEAWEED
Dlaza*, T.S.1, Maneveldt, G.W.1 & Viljoen, C.2 1 Dept. of Biodiversity & Conservation Biology, University of the Western Cape, South Africa. 2 Jacobsbaai Sea Products, Jacobsbaai, South Africa.
The relatively slow growth rate of abalone fed on macro-algae has prompted the development and use of various artificially formulated diets. However, most formulated diets are composed of animal-based protein that is expensive to produce. The primary objective of this research was to move towards developing and incorporating seaweed-based feeds into abalone diet formulations and then to test the growth of abalone (Haliotis midae) on these new diet formulations. This research was conducted at the Jacobsbaai Sea Products farm along the South African west coast. For this particular project, post-weaning juvenile abalone were used. Dietary treatments included a selection of formulated feeds: ABFEED, Adam & Amos and an all-seaweed-based dried formulated feed; the former two are animal-based dried formulated feeds. These feeds were compared against each other in a series of growth trials and were then fortified with fresh beach cast kelp and farm-grown, protein-enriched Ulva sp. An additional seaweed treatment (Ulva + kelp + mixed red seaweeds) was also used to test for variability among diets. The data shows that ABFEED outperforms all formulated feeds presently being used. Furthermore, formulated feeds fortified with fresh seaweed consistently produce better growth in post-weaning abalone.
Canning trials with kelp-fed and ABFEED-fed abalone have confirmed our observations that ABFEED-fed abalone provide a considerably higher canned meat yield. A research report of on-farm trials on the growth, FCR and meat yields in on-farm R&D conducted by Adele Hattingh will be posted on the website soon.
These results are supported by the results of Dr A. Vosloo, which clearly showed that ABFEED-fed abalone meat contains higher glycogen levels. Kelp does not contain sufficient protein for reserves to be built up.
Our strategy for the future of ABFEED is to maintain our position as the best formulated abalone diet available worldwide and to further improve the diet to the benefit of our clients. For that to happen, our R&D programme is being stepped up drastically. Research has been carried out at Rhodes University since 1992 to find the best formulations. This continues with the addition of work being done at Potchefstroom University (Dr Andre Vosloo).
Some of the work in progress :
A research report by Adele Hattingh on the growth, FCR and processing yields of Haliotis midae has been posted on this website. Growth and FCR is compared between 3 ABFEED diets and kelp over a period of 14 months. Meat yields were also determined and are reported on, indicating that ABFEED use dramatically increases meat yield.
Trials have been completed in the development of a 'stress diet' designed to be used mainly during stressful environmental conditions. The new product ABFEED K22 is available after extensive on-farm abalone growth- and yield trials. It was specifically formulated for farms with concerns for the danger of 'bloating' which can lead to mortality in abalone. ABFEED K22 has a low protein content, which reduces and will probably eliminate the danger of 'bloating'.
Highly stressful conditions in grow-out, such as water temperatures above the abalone's tolerance level, or a harmful algal bloom which releases toxins into the water, can lead to 'bloating' of the gut. It seems that sudden high stress can cause the passage of food through the gut to stop. This causes gas to be released from food in the gut and in extreme cases can puncture the gut and cause mortality.
The target market has been farms on the east coast of South Africa where warm water events during mid-summer have caused mortalities in the past.
Although no specific trials have been carried out, ABFEED K22 may be very suitable for recirculation systems, because of the low protein content of this formulation. Lower protein consumption will reduce ammonia excretion and relieve pressure on bio-filters. This should be particularly effective at temperatures of 16°C and above.
Protein requirement in abalone is reduced as they increase in size. Tests will be conducted to test this diet on larger abalone (above say, 120 g).