Effects of yeast and willow extract in the diet on the survival and growth parameters of the crayfish (Cambarellus montezumae)

The use of additives such as yeast or plant extracts in crayfish diets, even though are typically found in their natural habitats, has attracted recent attention due to the observed health, growth, and socio-economic benefits they offer. The presence of willow detritus in the stomach contents of free-living crayfish suggests its potential role in crayfish growth, even though it has not yet been demonstrated. This study aimed to evaluate the effect of yeast and willow extract as dietary additives on the growth of the crayfish Cambarellus montezumae. A total of 630 juvenile crayfish were collected, introduced into a recirculating aquaculture system, and randomly assigned to three treatment groups with three replicates each one (n = 70 per replicate): shrimp-balanced ration with yeast, shrimp-balanced ration with willow extract, and shrimp-balanced ration as the control. Throughout a 70-days period, the crayfish were weekly measured and weighed to assess various growth parameters and survival. Crayfish fed with the yeast ration showed improvements in weight, length, biomass, periodic absolute increase in weight and length, and relative growth rate in length compared with those in the willow and control groups. The incorporation of yeast into the ration demonstrates greater advantages to produce Cambarellus montezumae. The underlying mechanisms suggest efficient ration utilization and the potential for increased production which, has important implications for the aquaculture industry.