Ileal and total digestibility of amino acids in feeds used in mink and polar fox nutrition

Abstract

The results of research on the apparent ileal and total digestibility of nitrogen and amino acids in mink and polar foxes are presented. The research reveals lower values of apparent nitrogen and amino acid digestibility coefficients in the small intestine than in the whole alimentary tract of these animals fed on diets containing different sources of animal protein. Fresh fish proteins showed higher ileal and total digestibility of nitrogen and amino acids than fish meal proteins. The increase or sole content of fish meals in the diets caused more rapid digesta passage, a rise in the amount of voided faeces and lower apparent ileal and total digestibility of nitrogen and amino acids. After diets containing whole fish and beef, the amino acids with the highest digestibility were methionine and lysine. After the diets containing fish meal, meat meal, meat-and-bone meal, and poultry by-product meal, arginine was the amino acid that was the quickest to be absorbed from the small intestine in mink and polar foxes. The amino acids of the lowest availability in the small intestine, as well as in the whole alimentary tract of these species appeared to be threonine and cystine. The lowest apparent digestibility of these amino acids probably resulted from their high content in endogenous nitrogen released in the digestive tract of mink and polar foxes.

Nutrient digestibility in Arctic fox (Vulpes lagopus) fed diets containing animal meals

“…The values of digestibility coefficients, previously presented, can be considered typical of growing Arctic foxes aged four to five months, despite statistically significant differences between the control and experimental groups. These results are also consistent with the findings of other authors, regarding Arctic foxes Skrede, 1995, 1998;Gugołek et al, 1997;Lorek et al, 1999Lorek et al, , 2002Ahlstrom et al, 2000;Szymeczko, 2001;Dahlman et al, 2002;Matusevicius et al, 2004;Vhile et al, 2005a,b). Table 4 shows daily balance and retention of nitrogen.…”

“…In foxes, the digestion process requires the presence of enzymes (Oleinik, 1995;Szymeczko and Burlikowska, 1996). A comparative analysis of nutrient digestibility in Arctic foxes has been performed, among others, by Skrede (1995, 1998), Szymeczko (2001), Ahlstrom et al (2003), and Vhile et al (2005a).…”

Ileal and total tract nutrient digestibility in blue foxes (Alopex lagopus) fed extruded diets containing different protein sources

“…The foxes were in good health as ascertained by veterinary examination. 'End-to-end' ileorectal anastomosis (IRA-method) was carried out as described previously (Szymeczko, 2001). The digestibility experiment with IRA modified foxes started two months after surgery.…”

“…In farmed foxes feed evaluation has been based on total tract digestibility (Dahlman et al, 2002), while ileal digestibility is increasingly used for dogs (Meyer et al, 1988;Zuo et al, 1996;Hendriks & Sritharan, 2002;Propst et al, 2003). However, ileal digestibilities may be different from total tract values also in blue foxes (Szymeczko, 2001), probably depending on feed ingredients used and processing, as shown in dogs (Murray et al, 1997). Amino acids and other nutrients disappearing from the hindgut may not be available to the animal (Just et al, 1981).…”

“…Different methods have been applied to determine ileal digestibility in carnivores, i.e. ileal cannulation techniques (Zuo et al, 1996;Propst et al, 2003), intestinal dissection (Szymeczko & Burlikowska, 1996;Hendriks & Sritharan, 2002) or ileorectal anastomosis (IRA method) (Szymeczko, 2001). The latter method offers the advantage of allowing total collection of digesta or faecal material, thus being independent of the use of indigestible markers.…”