## 3 Results
### Gut Microbiota
\begin{table}
\begin{tabular}{l c c c c} \hline \hline
**Fatty Acid Group** & **HS0** & **HS1** & **HS3** & **HS6** \\ \hline SFA & 21.50 \(\pm\) 0.95 & 21.29 \(\pm\) 1.50 & 22.24 \(\pm\) 1.68 & 21.41 \(\pm\) 1.20 \\ MUFA cis & 48.35 \(\pm\) 1.38 \({}^{\rm ab}\) & 48.19 \(\pm\) 0.99 \({}^{\rm b}\) & 49.93 \(\pm\) 1.50 \({}^{\rm a}\) & 47.91 \(\pm\) 1.17 \({}^{\rm b}\) \\ PUFA cis & 29.24 \(\pm\) 1.54 \({}^{\rm a}\) & 29.58 \(\pm\) 0.99 \({}^{\rm a}\) & 26.71 \(\pm\) 2.12 \({}^{\rm b}\) & 29.66 \(\pm\) 1.68 \({}^{\rm a}\) \\ UFA cis & 77.59 \(\pm\) 0.95 & 77.77 \(\pm\) 1.49 & 76.64 \(\pm\) 1.69 & 77.57 \(\pm\) 1.13 \\ Trans isomers & 0.34 \(\pm\) 0.04 & 0.34 \(\pm\) 0.06 & 0.37 \(\pm\) 0.04 & 0.37 \(\pm\) 0.09 \\ Omega-3 & 8.73 \(\pm\) 0.89 \({}^{\rm a}\) & 8.86 \(\pm\) 0.58 \({}^{\rm a}\) & 7.27 \(\pm\) 1.13 \({}^{\rm b}\) & 8.49 \(\pm\) 1.05 \({}^{\rm ab}\) \\ Omega-6 & 20.52 \(\pm\) 0.79 \({}^{\rm ab}\) & 20.73 \(\pm\) 0.68 \({}^{\rm a}\) & 19.43 \(\pm\) 1.07 \({}^{\rm b}\) & 21.16 \(\pm\) 0.89 \({}^{\rm a}\) \\ Omega-3/omega-6 & 0.425 \(\pm\) 0.035 \({}^{\rm a}\) & 0.427 \(\pm\) 0.028 \({}^{\rm a}\) & 0.373 \(\pm\) 0.042 \({}^{\rm b}\) & 0.401 \(\pm\) 0.043 \({}^{\rm ab}\) \\
**Nutritional index** & & & & \\ PUFA/SFA & 1.36 \(\pm\) 0.11 \({}^{\rm ab}\) & 1.40 \(\pm\) 0.14 \({}^{\rm a}\) & 1.21 \(\pm\) 0.17 \({}^{\rm b}\) & 1.39 \(\pm\) 0.15 \({}^{\rm ab}\) \\ IA & 0.229 \(\pm\) 0.014 & 0.229 \(\pm\) 0.020 & 0.238 \(\pm\) 0.024 & 0.226 \(\pm\) 0.018 \\ IT & 0.332 \(\pm\) 0.026 & 0.328 \(\pm\) 0.031 & 0.371 \(\pm\) 0.049 & 0.335 \(\pm\) 0.035 \\ HH & 2.18 \(\pm\) 0.17 & 2.20 \(\pm\) 0.19 & 2.00 \(\pm\) 0.24 & 2.24 \(\pm\) 0.23 \\ UI & 130.0 \(\pm\) 5.7 \({}^{\rm a}\) & 130.3 \(\pm\) 3.6 \({}^{\rm a}\) & 121.0 \(\pm\) 7.2 \({}^{\rm b}\) & 130.6 \(\pm\) 7.1 \({}^{\rm a}\) \\ HPI & 4.37 \(\pm\) 0.26 & 4.40 \(\pm\) 0.38 & 4.24 \(\pm\) 0.41 & 4.44 \(\pm\) 0.35 \\ EPA + DHA & 3.34 \(\pm\) 0.84 \({}^{\rm a}\) & 3.29 \(\pm\) 0.51 \({}^{\rm a}\) & 2.28 \(\pm\) 0.79 \({}^{\rm b}\) & 3.35 \(\pm\) 0.89 \({}^{\rm a}\) \\ \hline \end{tabular} Note: Values are expressed as means \(\pm\) standard deviations (SD). The number of independent replicate experiments \(n=10\). Numbers followed by different lowercase letters in the same row are statistically different (\(p\leq 0.05\)).  
\end{table} 
Table 5: Sums of different groups of fatty acids (in relative % of all detected fatty acids) and their nutritional indices. The main microbiota of the analyzed samples comprised the following three genera: _Ralstonia_, _Pseudomonas_, and _Cetobacterium_; other genera were present in all the samples, but at a low relative abundance: _Staphylococcus_, _Bradyrhizobium_, _Bacillus_, and _Anaerobacillus_ (Figure 5). Figure 4: Alpha diversity measure of the microbiota in _C. gariepinus_ midgut samples (HS0–HS3). Figure 3: The principal component analysis (PCA) of microbiota in _C. gariepinus_ midgut samples (HS0–HS3). In particular, the relative abundance of _Pseudomonas_ decreased while the presence of _Cetobacterium_ increased in samples fed with 3% HS (Figure 6, \(p<0.05\)). The same samples showed the highest relative abundance of _Cetobacterium_ and _Plesomonas_ (Figure 6, \(p<0.05\)). _Anareococcus_ genus was more abundant in samples fed with 1% HS, while the relative abundance of _Acinetobacter_ genus decreased when the percentage of HS increased (Figure 6, \(p<0.05\)). Figure 5: The global composition of the microbiota displays the lowest taxonomic resolution of _C.gariepinus_ midgut samples at the genus or family level.