## 3 Results and Discussion
### Birds Performance and Welfare  
The number of repetition (two pens for treatment) was decided in order to avoid any change in management and environment of the animals that could bias the results. Studies with many repetitions with few animals (often kept in cages) x repetition generally aim to test the effect of  
Figure 1: Volatile compounds recognized in the Control and camelina diets (CAM10 and CAM20). Data expressed as arbitrary units refer to the peak area of the Quant ion (in brackets).  
some new ingredients in the diet. As the positive effect of camelina was already proven by several studies [18; 19; 21; 22; 49], the novelty of our paper is that camelina cake used conditions close to the farm ones, for a long period (31 weeks) and with a high percentage (up to 20%) of camelina cake in the diet. In light of this consideration, it is worth noticing that papers addressing applied research questions use the same approach [50].  
The number of eggs was not affected by the percentage of camelina cake in the diet (Table 4). Feed consumption was 128.57, 122.35, 114.04 g/hen per day for C, CAM10, and CAM20 hens, respectively. These data were similar to the results of [PERSON] et al. (2009) [21] that used camelina cake in three treatments (5%, 10%, and 15%); authors found that hen-day egg production was lowest for CAM15 and no differences among the other treatments. Feed consumption was 106.5, 105.2, 97.7, and 98.7 g/hen per day for control, CAM5, CAM10, and CAM15 birds, respectively. [PERSON] et al. (2012) [49] examined the effects of feeding extruded defatted camelina cake (5% and 10%) to layers and they found no differences in percent hen-day egg production and feed consumed. [PERSON] et al. (2007) [51] reported a reduction in feed intake when the diets contained more than 5% camelina in the diets of young turkeys. In this study, the use of camelina cake up to 20% in the diet did not negatively affect the production, feed consumption, and feed conversion rate (Table 4), suggesting that camelina cake could be an economic sustainable source of protein for poultry.  
Eggs production rate (eggs laid \(\times\) 100/number of hens) was similar among the three treatments according to the Hy-Line(r) standard. As shown in Figure 2, all treatments peak in egg production at the same time (26-27 weeks of age), the persistence of the deposition until the end of the production cycle was characterized by slowly reducing egg production; this picture is common in most layer flocks [52].  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Performance** & **C** & **CAM10** & **CAM20** \\ \hline Average Daily Intake (g/day/hen) & 128.57 \(\pm\) 4.94 & 122.35 \(\pm\) 5.03 & 114.04 \(\pm\) 6.12 \\ Egg production/week & 464.16 \(\pm\) 14.70 & 499.00 \(\pm\) 13.40 & 473.94 \(\pm\) 11.00 \\ Egg weight (g) & 62.64 \(\pm\) 4.26 & 62.16 \(\pm\) 3.77 & 61.79 \(\pm\) 3.72 \\ FCR & 2.44 \(\pm\) 0.10 & 2.19 \(\pm\) 0.12 & 2.22 \(\pm\) 0.11 \\ Initial hen/s weight (g) & 1872.5 \(\pm\) 30.9 & 1765.0 \(\pm\) 34.6 & 1782.5 \(\pm\) 35.4 \\ Final hen/s weight (g) & 2060.0 \(\pm\) 40.5 & 2065.0 \(\pm\) 35.2 & 2000.0\(\pm\)46.7 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Effect of camelina cake in laying hen diets on average daily intake, egg production, egg weight, and feed conversion ratio (FCR) from 21 to 51 weeks of age (Control diet—C, camelina diets—CAM10 and CAM20; mean \(\pm\) SE).  
Figure 2: Hen-day egg production (%) in the Control diet (C) and camelina diets (CAM10 and CAM20) vs. Hy-Line® brown standard (ST).