# From Feed to Fish--Nutrients' Fate in Aquaculture Systems
## 3 Results
### Fislpond and Cultivation Characteristics
#### 3.3.5 Feed and Fertilizers  
In the 23 budgeted papers we assessed, the feed application was mentioned in 20 papers and included a variety of feed types, including commercial feed (manufactured pellets), fish, cereals (wheat, rice, or maize bran), and plant components (plant wastes and crops residues). In some cases, specific feed was formulated to test the effect of different ingredients and dosages on fish growth (Table 5). Nonetheless, among the papers that quantified the amount of C, N, and P input via feed, the most common type of feed used was commercial feed. Low contribution of feed to the carbon inputs (<35%) was found in four of the assessed papers in different cultivation systems and species [13; 16; 25; 31]. A contribution of up to 95% was reported in studies in polyculture carp ponds (_Catla calla_, _Laboe rolita_, and _Cirrhinus mrigala_) [17; 18]. Overall, the contribution of fertilizer to the inputs of carbon was less than 10%, except for the integrated (IAA) fishponds, where fertilizer was composed of excreta and crop residues, accounting for 65% of the C input. Lower contribution (<30%) to the inputs of nitrogen was registered in a few studies, either receiving commercial feed [24], rice bran, or mustard oil cake [37]. Contribution of over 50% of the nitrogen inputs was commonly registered across different studies, using commercial feed, fish, or wheat as feed sources or in fertilized ponds. As for phosphorus, the lowest contribution of feed was already around 50% of the inputs [14], and the contribution of more than 70% was registered in many of the assessed papers. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Reference** & **Fish Species** & **C (\%)** & **kg ha\({}^{-1}\) d\({}^{-1}\)** & **N (\%)** & **kg ha\({}^{-1}\) d\({}^{-1}\)** & **P (\%)** & **kg ha\({}^{-1}\) d\({}^{-1}\)** \\ \hline
[14] & _Heterobranchus longifilis_ & n.r. & n.r. & n.r. & n.r. & 2 & 0.006 \\
[15] & _Carassius carassius_ & n.r. & n.r. & n.r. & n.r. & 26 & 0.5 \\ _Iclaturus punctatus_, hybrid & & & & & & \\ channel catfish, hybrid channel & & & & & & \\
[16] & catfish (_Iclaturus punctatus_ & 3.5 & 8 & n.r. & n.r. & n.r. & n.r. \\ \(\times\)_Iclaturus truncatus_), _Polyodon_ & & & & & & \\ _spathula_, and _Oreochromis niloticus_ & & & & & & \\
[21] & _Oreochromis niloticus_ & n.r. & n.r. & 1 & 0.04 & n.r. & n.r. \\
[22] & _Oreochromis niloticus_ & n.r. & n.r. & n.r. & n.r. & 1.3 & 0.01 \\
[24] & _Colossoma macropomum_ & n.r. & n.r. & 0.2 & 0.02 & n.r. & n.r. \\
[25] & _Colossoma macropomum_ & 0.10 & 0.03 & n.r. & n.r. & n.r. & n.r. \\
[26] & _Colossoma macropomum_ & n.r. & n.r. & n.r. & n.r. & 0.2 & 0.001 \\
[27] & _Osphurements gorny_ & n.r. & n.r. & 3 & 0.3 & 0.7 & 0.02 \\
[28] & _Iclaturus punctatus_ & n.r. & n.r. & 2 & 0.04 & n.r. & n.r. \\
[29] & _Oreochromis niloticus_ & n.r. & n.r. & 5 & 0.05 & 2 & 0.02 \\ _Channa arguss_ and & & & & & & & \\ _Hypothalmichtphys nobilis_ & n.r. & n.r. & 0.2 & 0.003 & 0.1 & 0.0004 \\
[31] & _Microterus salmonides_ & 0.3 & 0.2 & 0.7 & 0.1 & 0.5 & 0.01 \\
[33] & _Cyprinus carpio_ & n.r. & n.r. & 36 & 0.05 & 28 & 0.01 \\ Hybrid catfish (_Clarias_ & & & & & & \\ _macrocephalus \(\times\)_Clarias gariepinus_) & n.r. & n.r. & 3 & 0.5 & 2 & 0.06 \\ and _Oreochromis niloticus_ & & & & & & \\ _Cyprinus carpio_ & n.r. & n.r. & 11 & 0.2 & 26 & 0.06 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Contribution of stocked fish to the total input of carbon, nitrogen, and phosphorus and its rates (kg ha\({}^{-1}\) d\({}^{-1}\)). Values shown in the table are the mean of the values reported in the assessed papers. n.r. : not reported.