Effect of different dietary crude protein levels on performance, N digestibility and some blood parameters in Kivircik lambs

Abstract

In this study, 45 weaned Kivircik male lambs with an average initial body weight ŠBW¹ of 26.23 kg were randomly assigned to five experimental groups (G10, G12, G14, G16, G18) fed 10, 12, 14, 16, 18 % crude protein (CP), respectively. It was observed that G16 had higher BW than the first three groups (p<0.05), but there were no significant differences between G16 and G18. G16 had higher daily body weight gain ŠBWG¹ than other groups. During the study, when compared with first three groups, G16 had significantly higher BWG (p<0.05), but no significant difference was observed between G16 and G18. The lowest DMI was observed in G10 (p<0.05), however, there were no differences between G14, G16 and G18. The best and the lowest feed efficiency were observed in G16 and G10, respectively. When the analysis results of faeces samples were compared, the lowest nitrogen (N) excretion was detected in G10 and G12, and the highest N excretion was detected in G18 (p<0.05). However, there were no significant differences between G14 and G16. Percentages of N digestibility's of G16 and G18 were higher than those of other groups (p<0.05). There were no significant differences between G16 and G18, and between G10, G12 and G14. The analysis results of serum samples obtained from experimental groups showed that, except for serum urea and albumin levels, there were no significant differences between the level of other metabolites. G10 had lowest serum albumin level (p<0.05), and there were no significant differences between the other groups. Serum urea levels of G14, G16, G18 were similar and higher than those of G10 and G12 (p<0.05). The lowest serum urea level was determined in G10 (p<0.05). Consequently, when it was considered that feeding Kivircik lambs with higher protein level than 16 % had no advantage for performance and would be cause of economic loss, it can be said that 16 % CP was optimal

Farklı Düzeylerde Protein İçeren Konsantre Yem Karışımının Bafra Irkı Kuzularda Besi Performansı, Sindirilebilirlik, Bazı Rumen ve Kan Parametrelerine Etkisi

“…In this study, the feed intake of the three experimental groups ranged from 1.215 to 1.254 g/day. These results support those of Bilal et al [8] who reported that the lowest dry matter intake was observed at the 10% CP level. Also, many researchers have reported no effect of dietary CP content on DMI [23,24] .…”

“…In the current study, the average final weight was highest (P<0.05) for the 17% CP diet, followed by 14 and 11% (Table 2). Improved growth performance was also reported at higher dietary CP levels (16 to 18%) than at lower CP levels (10 to 14%) by Awassi [9,29] and in Kıvırcık lambs [8] . Similarly Kaya et al [11] and Abbasi et al [30] reported higher growth for Morkaraman and Kooka lambs, respectively, at higher CP (16%) than at a lower level of dietary CP.…”

“…Diseases and nutritional disorders can induce changes in blood parameters. The evaluation of the effects of dietary CP level on blood metabolites is therefore important [8] .…”

“…Rumen NH 3 -N and VFA levels increased with increasing dietary CP level [11,[13][14][15] . Separately, it has been reported that there was no significant effect of dietary CP level on glucose and total serum protein levels, except for urea [8,16] .…”

“…Though feeding lambs an 18% CP diet is conventional practice, there was no difference between lambs fed 16 and 18% CP which both had a significantly higher body weight gain and DM intake than lambs fed a 10, 12 or 14% CP diet. The authors also emphasised that there were no benefits of using diets with higher than 16% CP [8][9][10] . Some studies have reported that DM and OM digestibility levels were not significantly different among different dietary levels of CP (10-17%), but CP digestibility levels were significantly higher in lambs feed higher CP levels [9,11,12] .…”