Just like endogenous enzymes, feed enzymes also have a temperature-activity profile, but feed enzymes have an advantage in that they can be designed to work effectively across a wider temperature range. Among metabolic processes, the effect of temperature on the rate at which numerous enzymes work is perhaps the most relevant, since efficiency of digestive processes and nutrient uptake are highly enzyme dependent. Extreme temperatures, either high or low, will result in death and high mortality of the farm crop. Temperatures above the optimum range cause metabolic processes to race, wasting energy and nutrients. Temperatures below the optimal range reduce feed intake, a result of depressed metabolism and reduced energy needs, leading to slow growth. Since aquatic animals are unable to control their body temperature, keeping water temperatures in the optimal range is essential to attain maximum growth. For example, a feed high in soybean meal could benefit from adding a combination of galactosidase, glucanase and mannase, to break down the equivalent NSPs prominent in soybean meal. The secret to using carbohydrase enzymes most effectively is to match the enzyme or combination of enzymes specifically designed to break down the indigestible carbohydrates found in most plant-based feeds.
These enzymes increase available dietary energy by converting starch oligosaccharides and non-starch polysaccharides (NSP) into simple sugars, and by breaking down cell walls, unlock more protein and lipids to be extracted and utilised by animals. Enzymes to assist digestion of complex carbohydrates – among them amylases, glucanases, mannanases and xylanases – have been used in poultry feeds for decades, and research with fish and shrimp has shown that these enzymes work well when added to aquafeeds for many species. Rather than waiting for long-term genetic improvement programmes to modify fish to be better at utilising plant-based ingredients, the rapid solution is to immediately start using carbohydrase enzymes in feed.
The salmon and trout farming industries have begun to select and breed animals that are more tolerant of soybean meal and other vegetable proteins (Quinton 2007, Overturf 2013, Callet 2017), but selective breeding for vegetable ingredient tolerance has not begun for Asian farmed fish and shrimp species yet. As the worldwide aquaculture industry strives to become more sustainable through the reduction of fishmeal in feeds, the ability of aquatic animals to effectively digest and absorb all the nutrients in alternative feed ingredients used in low fishmeal feeds becomes more and more important. One area where breeding programmes for genetic improvement are lagging is in enhancing the ability of omnivorous and carnivorous fish and shrimp to better utilise protein, amino acids and lipids in plant-based ingredients. A hatchery will often provide growth rate data so the farmer can determine whether performance on the farm is at standard, above standard or below standard. A typical farm will seek out fish fingerlings and shrimp post-larvae (PL) from a convenient reputable hatchery, based on historical performance.
#FEED AND GROW FISH SURVIVAL COINS PLUS#
This is based on the degree of domestication, plus any genetic improvement.
The aim of this article is to highlight the ways in which supplementing feeds with protease, carbohydrase and phytase enzymes can improve outcomes for each of these factors relating to farm animal performance.