Nitrogen and energy balance in growing mink (Mustela vison) fed different levels of bacterial protein meal produced with natural gas

Abstract

The objective of this study was to estimate the effect of increasing the dietary content of bacterial protein meal (BPM) on energy and protein metabolism in growing mink kits. Sixteen male mink kits of the standard brown genotype were randomly fed one of four diets: A control (Diet I) based on high-quality fish meal, and three experimental diets in which 20% (Diet II), 40% (Diet III) and 60% (Diet IV) of the digested nitrogen (DN) was replaced with BPM. Nitrogen balance and respiration experiments (indirect calorimetry) were carried out when the animals were approximately 9.5, 14.5, 17.5, 23.5 and 28.5 weeks of age. The apparent digestibility of crude protein and energy decreased significantly with increasing dietary BPM. The retained nitrogen was 0.45, 0.54, 0.52 and 0.40 g/kg0.75 on Diets I, II, III and IV, respectively, the observed differences between diets being non-significant (p = 0.06). Heat production (HE) was between 645 and 665 kJ/kg0.75 on all diets (p = 0.78). Retained energy (RE) was approximately 150-160 kJ/kg0.75 on Diets I to III, whereas it was -11 kJ/kg0.75 on Diet IV, the differences being significant (p< 0.001). A lower feed intake and apparent digestibility of energy caused the negative RE on Diet IV. The amount of HE from oxidation of protein decreased from 32.7% on Diet I to 26.6% on Diet IV, and oxidation of fat increased from 53.8% on Diet I to 63.5% Diet IV. In conclusion, protein and energy metabolism remained unaffected when up to 40% of DN was derived from BPM.

Bacterial protein meal in diets for growing pigs: effects on protein and energy metabolism

“…Despite less protein being available for retention and the lysine content in the diets being slightly below the NRC (1998) recommendations, the RN on BP15 was only slightly and non-significantly lower than the highest value, which was found on diet BP5. This result concurs with our findings in mink, where RN was unaffected by dietary BPM level (Hellwing et al, 2005). In slaughter chickens, Hellwing et al (2006) also found similar RN levels for all BPMcontaining diets.…”

“…Energy metabolism Increasing inclusion of BPM in the diet did not affect HE in growing pigs, which is in agreement with the results of previous studies on mink (Hellwing et al, 2005) and slaughter chickens (Hellwing et al, 2006). This means that even if assuming 100% digestion of the purine and pyrimidine bases, the energy cost for the excretion of their metabolites would be small in relation to other metabolic processes.…”

“…A high-quality protein source must sustain high N retention and not cause elevated heat production (HE). Effects of including BPM in the diet on protein and energy deposition are still limited to studies in chicken and mink, which showed that retained nitrogen (RN) remained unaffected when BPM made up 20 to 60% of digestible N in the mink diet (Hellwing et al, 2005) or 6.5 to 20% in the chicken diet (Hellwing et al, 2006). The heat production in mink (Hellwing et al, 2005) as well as in chickens (Hellwing et al, 2006) was the same on the control diet and the diets with BPM.…”

“…Previous production experiments with BPM in diets for monogastric species (Øverland et al, 2001 andSkrede and Ahlstrøm, 2002;Skrede et al, 2003;Storebakken et al, 2004), and N and energy metabolism studies in mink and chickens (Hellwing et al, 2005 and2006), have given somewhat varying and contradictory results. Therefore, the objective of the present study was, by means of balance and respiration experiments, to reveal effects of replacement of SBM by BPM on N and energy metabolism in balanced diets for growing-finishing pigs.…”

Effects of growth substrate and partial removal of nucleic acids in the production of bacterial protein meal on amino acid profile and digestibility in mink

“…In pigs and mink, increased intake of nucleic acid nitrogen from BPM resulted in increased allantoin excretion (Hellwing et al, 2007). However, increasing levels of BPM have been fed without significant effects on nitrogen retention in pigs (Hellwing et al, 2007) and mink (Hellwing et al, 2005(Hellwing et al, , 2007Ahlstrøm et al, 2006). Recent studies by Aas et al (2006) showed higher nitrogen retention when bacterial protein meal partially replaced high-quality fish meal in diets for Atlantic salmon.…”