**4. Discussion**

In addition, the exposure of prawn fed fortified diets to *Pseudomonas aeruginosa* infection was presented in **Table 5**. The result indicated that there was significant difference (p < 0.05) in survival rate and relative protection of prawn fed fortified diets. Highest survival rate and relative protection were recorded in group fed 105 cfu/mL *Lactobacilus acidophilus* inclusion

Means with different superscripts are significantly different (p < 0.05), while, absence of letters means no significantly

**Table 4.** Innate immune response parameters of *Macrobranchium vollenhovenii* fed diets fortified with *Lactobacillus* 

**Control 101 102 103 104 105**

RBA 165.4 ± 2.17a 163.1 ± 3.13a 172.8 ± 1.11b 188.0 ± 2.15b 215.4 ± 2.46 243.7 ± 2.85 THC 12.06 ± 0.26a 13.11 ± 0.05 13.53 ± 0.l8 14.02 ± 0.17 14.65 ± 0.78 14.82 ± 0.16 PO (U/mL) 3.24 ± 0.43a 3.51 ± 0.07 4.07 ± 0.16 4.33 ± 0.09 4.89 ± 0.31 5.21 ± 0.34 ROI 5.27 ± 0.21a 6.02 ± 0.15 6.31 ± 0.34 6.38 ± 0.21 6.54 ± 0.23 6.79 ± 0.29

0.41 ± 0.01a 2.45 ± 0.02ab 3.62 ± 0.05b 6.33 ± 0.15 6.57 ± 0.55 6.82 ± 0.22

1.51 ± 0.02a 2.04 ± 0.04a 2.74 ± 0.01 3.06 ± 0.20 3.47 ± 0.21 3.85 ± 0.04

8.13 ± 0.62a 11.20 ± 0.38a 13.05 ± 0.03 13.46 ± 0.78 13.78 ± 0.19 14.02 ± 0.18

**Table 6** reveals the resistant of *Macrobranchium vollenhovenii* to *Aeromonas hydrophila* infection. Survival and relative protection of prawn to *Aeromonas hydrophila* were significantly different (p < 0.05). Prawn fed 105 cfu/mL *Lactobacilus acidophilus* inclusion level had highest survival and relative protection rates while the prawn treated control diet had the lowest survival and

Means with different superscripts are significantly different (p < 0.05), while, absence of letters means no significantly

**Table 5.** Resistant of *Macrobranchium vollenhovenii* fed diets fortified with *Lactobacillus acidophilus* to *Pseudomonas* 

**Initial stock Survival (%) Relative protection**

level and least were recorded in control group.

*Lactobacillus acidophilus* **inclusion levels (cfu/mL) Parameters (log10cfu/mL)**

Control 30 23.3 ± 0.03a 0.00 ± 0.00a 30 40.0 ± 0.13b 21.74 ± 0.15b 30 73.3 ± 0.23c 65.22 ± 0.16c 30 86.7 ± 0.71 82.61 ± 0.37 30 93.3 ± 0.11 91.30 ± 0.21 30 96.7 ± 0.42 95.65 ± 0.02

*Lactobacillus acidophilus* **inclusion levels (cfu/mL)**

relative protection rates.

different (P > 0.05).

*aeruginosa* infection.

**Parameters (log10cfu/mL)**

100 Aquaculture - Plants and Invertebrates

SOD (mg/g protein)

CAT mg/g protein)

Lysozyme activity

*acidophilus*.

different (P > 0.05).

The result of the gut flora revealed that there were reductions in the bacteria load of the prawn fed fortified diets. The decrease in the in observed could be attributed to the activities of *Lactobacillus acidophilus* as probiotics which modulate the gut pH to its favour and outcompete the pathogenic organisms. According to International Commission on the Microbiological Specification of Foods [21] the acceptable level of bacterial load in fish tissue should be lower than 5.70 Log10cfu/g. In this study, the TVC and TEB of prawn fed fortified diets were within the recommended values except the control and fish fed 10<sup>1</sup> cfu/ mL of *Lactobacillus acidophilus*. The reduction in the load of bacteria especially TEB signifies that the probiotics improve the gut of the prawn by outcompete the pathogenic bacteria. The gut flora comprises *Pseudomonas aeruginosa, Aeromonas hydrophila,* Bacillus species and *Staphylococcus* species. Fish fed *Lactobacillus acidophilus* based diets had higher gut flora dominated by *Bacillus* species that the fish fed control diet and reduction of pathogenic organisms were observed. The findings of this study are in agreement with the work of [22] who reported that probiotics enhanced the population of beneficial bacteria and suppressed the growth of pathogenic bacteria.

Gut flora have continuous and dynamic effect on the host's gut and systemic immune systems. The bacteria are key in promoting the early development of the gut's mucosal immune system both in terms of its physical components and function. The bacteria stimulate the lymphoid tissue associated with the gut mucosa to produce antibodies to pathogens [23]. The immune system recognises and fights harmful bacteria, but leaves the helpful species alone, tolerance developed in juveniles [24]. Recent findings have shown that gut bacteria play a role in the expression of toll-like receptors (TLRs) in the intestines, molecules that help the host repair damage due to injury. The TLRs are one of the two classes of pattern-recognition receptors (PRR) that provide the intestine the ability to discriminate between the pathogenic and commensal bacteria [25]. These PRRs identify the pathogens that have crossed the mucosal barriers and trigger a set of responses that take action against the pathogen [26].

**5. Conclusion**

**Author details**

Ibrahim Adeshina1

University, Australia

**References**

*Aeromonas hydrophila* infection.

Mozeedah Modupeola Ajibola3

Italy: FAO; 2016. p. 24

2014;**13**:798-813

2010;**29**:2-14

*Macrobranhium vollenhovenii* fed diets supplemented with *Lactobacillus acidophilus* had reduced total enterobactericeae in the gut, enhanced innate immune response parameters and suggest it usage as immunomodulation and protective agent against *Pseudomonas aeruginosa* and

and Akeem Babatunde Dauda4

2 School of Environmental Life Sciences, Faculty of Science and Built Engineering, Deakin

[1] Adeshina I, Adewale YA, Tiamiyu LO. Growth performance and innate immune response of *Clarias gariepinus* infected with *Aeromonas hydrophila* fed diets fortified with

[2] FAO (Food and Agriculture Organisation of the United Nations). The State of World Fisheries and Aquaculture: Contributing to Food Security and Nutrition for all. Rome

[3] Adedeji OB, Okocha RC. Constraint to aquaculture development in Nigeria and way

[4] Ajani EK, Akinwole AO, Ayodele IA. Fundamentals of Fish Farming in Nigeria. 1st ed.

[5] Jami M, Ghanbari M, Zunabovic M, Domig KJ, Kneifel W. *Listeria monocytogenes* in aquatic food products–A review. Comparative Review of Food Science and Food Safety.

[6] Nayak SK. Probiotics and immunity: A fish perspective. Fish and Shellfish Immunology.

forward. Journal of Applied Science and Research. 2011;**7**:1133-1140

Vol. 158. Ibadan: Walecrowns Ventures Nigeria; 2011

*Curcuma longa* leaf. West Africa Journal of Applied Ecology. 2007;**25**(2017):79-90

4 Department of Fisheries and Aquaculture, Federal University Dut-sima, Nigeria

, Lateef Oloyede Tiamiyu1

Gut Microbiota and Innate Immune Response of *Macrobrachium vollenhovenii* Infected…

,

http://dx.doi.org/10.5772/intechopen.78010

103

\*, Yusuf Adetunji Adewale2

1 Department of Aquaculture and Fisheries, University of Ilorin, Nigeria

\*Address all correspondence to: adesina.i@unilorin.edu.ng

3 Department of Zoology, University of Lagos, Nigeria

Also, [27] claims that different species of gut flora could influence the development of key cells of the immune system, by increasing or decreasing the level of tolerance against foreign entities. Once the host immune system is developed, it regulates the bacterial composition in the gut. One of the regulation mechanisms—immune exclusion—is mediated through the neutralisation of secreted immunoglobulin A (IgA) [28].

Harmful bacteria species, such as *Pseudomonas aeruginosa* and *Aeromonas hydrophila*, are unable to grow excessively due to competition from helpful gut flora species adhering to the mucosal lining of the intestine; thus, fish without/with low gut flora are infected very easily [28]. The barrier effect protects hosts from both invading species and species normally present in the gut at low numbers, whose growth is usually inhibited by the gut flora [29]. Helpful bacteria prevent the growth of pathogenic species by competing for nutrients and attachment sites to the epithelium of the colon. Also, symbiotic bacteria are more at home in this ecological niche and are thus more successful in the competition. Probiotics also produce bacteriocins, which are proteinaceous toxins that inhibit growth of similar bacterial strains, substances that kill harmful microbes and the levels of which can be regulated by enzymes produced by the host. Also, the process of fermentation produces lactic acid and different fatty acids, which lowers the pH in the colon, preventing the proliferation of harmful species of bacteria and facilitating that of helpful species [30].

Immune responses of the prawn fed fortified diets were higher than the control. There higher SOD, CAT RBA, THC, PO, ROI and lysozyme activity in prawn fed the *Lactobacillus acidophilus*based diets than in those fed control diet. Similar observations were made by [22, 31] in fish fed probiotics diets. The SOD, CAT RBA, THC, PO, ROI and lysozyme activity have important roles in the innate immune defence system. For instance, it was reported that lysozyme activity plays a significant role in innate humoral immune factors that control intrusiveness of pathogens by destroying the cell walls of the bacteria [1]. The SOD catalyses the dismutation of the superoxide anions to molecular oxygen and hydrogen peroxide, which further catalyses to water and oxygen. The SOD and CAT play an important role as cellular antioxidants against reactive oxygen species. In this study, prawn fed fortified diets had increased values of SOD, CAT, RBA and lysozyme activity, which could be answerable for the increased concentration of hydrogen peroxide in the oxidation process. The chemicals are released from immune cells and enzymes, as they come in contact with pathogens cumulating into improved immunity.

The investigation into the resistance level of *Macrobranchium vollenhovenii* fed diets fortified with *Lactobacillus acidophilus* revealed that the prawn were protected that the group fed control diet. In this study, prawns were significantly protected against *Pseudomonas aeruginosa* and *Aeropmonas hydrophila* infection with relative protection up to 96%. Similarly, [32–33, 7] reported that there was significant increase in the survival rate of fish fed *Lactobacillus acidophilus* fortified diets. The protection of prawn against the pathogens could be attributed to the gut serves as an entry point through feeding and thus inhibit the growth and survival of the pathogens.
