**3.1 Current status and application of the probiotics to medfly sterile males production system**

The term "probiotic" is derived from the Greek words pro and bios, which mean "life" [24]. It was coined in 1965 by Lilly and Stillwell [25] to contrast the term "antibiotic". The definition of probiotic' has evolved. The Food and Agricultural Organization and World Health Organization (FAO/WHO) define probiotics as "live microorganisms that, when administered in adequate amounts, confer a health benefit on the host" [26]. Many species have been designated as "Generally Recognized As Safe" (GRAS) with the origin of the strain, antibiotic resistance, and lack of pathogenicity determining the safety of probiotic strains [27]. Different Gram-positive bacteria belonging to the genus *Lactobacillus*, *Enterococcus*, *Bacillus*, and *Bifidobacterium* have been studied extensively for their role as probiotics.

Pioneering studies on the experimental use of probiotics were initiated following the interesting findings of Ben Ami et al. [16], working on medfly, that regenerating the original microbiota community could result in enhanced competitiveness of the sterile flies. We should also mention that this study, which partially replicated the work of Niyazi et al., [28], shed light on the composition of the intestinal microbiota in sterile males.

As demonstrated by Ben Ami et al., [16], the addition of Streptomycin-resistant *K. oxytoca* strain to the post-irradiation adult diet allowed this probiotic to colonize the guts of *C. capitata* sterile males. Currently, the most common method of medfly administration is oral administration via diet [17, 29, 30]. Indeed, probiotics could be given to medfly at two stages: larval and adult. If the addition occurs during the larval stage, there is only one option: add the probiotics as a suspension, usually 10<sup>7</sup> , 10<sup>8</sup> , 10<sup>9</sup> CFU/g mixed with the diet (carrot or wheat bran). If the addition occurs during the adult stage, there are two options: the first is to incorporate it into the adult diet as a bacteria-containing diet (granular sugar and yeast mixture or agar) [28], and the second is to introduce it through a cotton pad soaked with the bacterial suspension [2, 13, 16, 29, 31–35]. If multiple strain preparation is of interest in aquaculture, single administration for insects in general and medfly, in particular, is the option. As shown in **Table 1**, most of the studies exploited the probiotic strains as live; however, other


### *Advances in Probiotics for Health and Nutrition*


**Table 1.** *Summary of probiotics use in medfly SIT application.*
