The effect of extruded rapeseed feed on laying performance and quality of eggs

The goal of our study was to find the effect of extruded rapeseed feed on p roduction performance and on the quality of eggs of the Isabrown hens. The feed contained rapeseed, wheat, and peas at a ratio of 3 : 4 : 3. There was 45% of this combination feed in the mixtures. This rapeseed feed was fed r aw (groups NEEXTR45) or extruded (groups EXTR45). There were four trials wi th sixteen hens in each group [2 x (4 x 16)]. The experimental mixtures wer e fed ad libitum to the hens starting from their 21 weeks of age. All hens' eggs were weighed when the hens were between 21st and 41st weeks of age. F rom 42nd to 50th weeks of age we recorded the number of eggs and we weighed them when we analyzed the quality of eggs. We analyzed the quality of eggs every 28th day, by determining the weight of eggs, the weight of yolk and albumen, yolk color, Haugh units, and the strength, weight and thickness of the eggshell. We also observed the feed consumption at weekly intervals. T he average contents of glucosinolates in the mixtures were 0.855 mmol/kg in dry matter for the groups NEEXTR45 and 0.765 mmol/kg in dry matter for the groups EXTR45. The results of production performances are summarized in Ta bles 5 and 7. The average frequency of egg production during the period fro m 21 to 50 weeks of age was 93.4 +/- 0.896% in groups NEEXTR45 and 94.2 +/- 0.828% in groups EXTR45. Fig. 1 shows the pattern of egg production. We ob served the largest difference in egg production between the groups in the p eriod between the 29th and 47th week of age. The average daily feed consump tion (from 21 to 50 weeks of age) was 110.7 +/- 1.209 g/hen (groups NEEXTR4 5) and 102.8 +/- 1.027 g/hen (groups EXTR45). The difference of 7.9 g/hen/d ay was statistically significant (P < 0.01). Fig. 4 shows the influence of extrusion on feed consumption. Jeroch et al. (1995) registered only a sligh t decline in feed consumption because of the treatment. The average weight of eggs was 60.44 +/- 0.361 g (NEEXTR45) and 59.37 +/- 0.305 g (EXTR45). Th e difference of 1.07 g was not statistically significant. Fig. 2 shows the graph of the weight of eggs. The higher weight of eggs was caused by the hi gher intake of nutrients in groups NEEXTR45. Conversely, Jeroch et al. (199 5) did not observe the higher weight of eggs in the different groups, which were fed the expeller treated rapeseed. The average daily egg mass product ion was lower in groups EXTR45 (56.54 +/- 0.542 g/hen) in comparison with g roups NEEXTR45 (57.43 +/- 0.592 g/hen). The difference between the groups ( 0.89 g/hen) was caused by the higher weight of eggs in groups NEEXTR45, but it was not statistically significant. Fig. 3 shows the egg mass production during the experiment. The feed conversion ratio was 1.95 +/- 0.042 kg/kg in groups NEEXTR45 and 1.83 +/- 0.034 kg/kg in groups EXTR45. The differenc e 0.12 kg/kg was not statistically significant. When we used 13.5% of rapes eed in the mixtures, we reached a better feed conversion ratio than Jeroch Et al. (1995), who used 10% of the expeller treated rapeseed in the mixture for hens. But, he reached a better feed conversion ratio for the hydrother mically expeller treated rapeseed for both laying hybrids. The quality of a lbumen expressed by Haugh units achieved the levels of 84.15 +/- 0.7099 (NE EXTR45) and 82.05 +/- 0.7198 (EXTR45). The difference of 2.1 Haugh units wa s not statistically significant. The strength and thickness of the eggshell was not influenced by the treatment. We did not observe any health problem s of the hens during the experiment. We achieved higher egg laying producti on than in the hybrid standard (1996). We used 13.5% rapeseed in the mixtur es. From our recorded data we calculated the equations for egg laying; producti on at the age from 23th to 50th weeks. The equations are for NEEXTR45 y = - 0.0119 x(2) + 0.0184 x + 97 and for EXTR45 y = -0.0144 x(2) + 0.1431x + 97. The average weight of eggs was almost the same as the hybrid standard indi cates (60.0 g). We conclude that extrusion increases the utilization of nut rients because of better feed conversion ratios in the groups which receive d extruded rapeseed feed.