Nucleotides are normal components of the diet and the body provides mechanisms for their absorption and incorporation into tissues (Sanchez-Pozo & Gil, 2002). However, during periods of intensive development, nucleotide availability could limit the maturation of fast dividing tissues with low biosynthetic capacity, such as the intestine (Leleiko et al, 1983; Van Buren & Rudolph, 1997).

In chickens, dramatic changes occur in the development of the small intestinal mucosa after hatching, including enterocyte maturation, intensive cryptogenesis and villous SCIENTIFIC PUBLICATIONSN Efficacy of a nucleotide preparation in broiler chickens E. Esteve-Garcia, D. Martínez-Puig, E. Borda and C. Chetrit ( 2007 ), XVI European Symposium on poultry nutrition growth (Geyra et al, 2001). This intestinal development influences the growth rate, since intestinal maturation plays a rate determining role in providing the substrates for growth (Smith et al, 1990).

Nucleotide supplementation has been demonstrated to accelerate intestinal maturation both in humans (Sanchez-Pozo & Gil, 2002) and pigs (Martinez-Puig et al, 2007), but to date no information is available on chickens. The aim of the present experiment was to study the effect of nucleotide supplementation on productive performance of broiler chickens.

Nine hundred and sixty day-old broiler chickens of the Ross 308 strain were allocated by sex into 24 pens, assigned one of three treatments which consisted of three levels of supplementation of the nucleotide preparation (Nucleoforce®) in the diet: 0, 500 and 1000 mg/kg feed.

 

Performance during the experiment is shown in Table 1.

 

 

Results suggest that the more significant effects observed in the first 3 weeks reflect the greater need for nucleotides during this period of fast cell proliferation, as the chicken multiplies its initial body weight by a factor of more than 20, and also suggests that availability of nucleotides limits performance during this period. These results are in agreement with Tipa (2002) who showed that broiler chicks fed diets containing nucleotides from yeast extracts, had higher average live body weight, body weight gain and better feed conversion from the first to the fourth week of life. However in other trials (Owens & McCracken, 2007; Deng et al 2005) no clear effects of nucleotide supplementation on productive performance have been observed. Differences among trials could be related to the content of available nucleotides in the source of nucleotides used.
In the experimental trial, the lack of positive effect of the high level during the first 3 weeks could suggest that the cost of disposal of excess nucleotides may compensate the improvement in performance. However, this effect is not observed in the last 3 weeks, suggesting that chickens may need some adaptation to utilize a higher levels of nucleotides.