PSXIII-12 Effects of altitudinal floor on nutrient digestibility, energy efficiency, visceral organ mass, and performance by guinea pigs.

An experiment was conducted to evaluate the effect of altitude on nutrient digestibility, energy efficiency, performance, and, visceral organ mass by guinea pigs. Twenty male guinea pigs (initial BW 1.011 ± 0.096 kg) were selected in a crossover design experiment, maintained at metabolic cages (2 animals per cage) during a total digestibility period of 25 d (2 periods of 13-d). Animals were randomly assigned at 1 of 2 altitudinal sites, 2986 and 2480 m. above the sea level (masl; 5 cages per altitude). Animals were fed 45 g of alfalfa (DM) to meet energy requirements at maintenance levels. At the end of the digestion phase, an animal from each cage was slaughter to determine body fat content from body specific gravity and visceral organ mass. A subsequent performance phase was evaluated as completely randomized design, and animals were kept at the same altitudinal floor in which they ended period 2 of the crossover period. Animals were fed ad libitum with alfalfa. At the end of the performance phase, all remaining animals were slaughtered and visceral organ mass was measured. Energy intake and Dry matter, were increased by animals at 2986 compared to animals at 2480 masl (P<0.001). Metabolizable energy tended to be lower for animals kept at 2986 masl (P=0.053). Nutrient digestibility was lower for animals kept at 2986 compared to 2480 masl. Liver, kidneys and spleen mass were greater for animals maintained at 2986 masl (P<0.012). Heart mass tended to be greater for animasl kept at 2480 masl (P=0,060). Body fat was not alterd by altitudinal site (P>0.345). Final BW, ADG, and feed conversion rate was decreased by animals fed at 2986 masl (P<0.002). Results from this experiment suggest a novel approach to determine Energy efficiency as affected by altitudinal site. Data from this experiment evidenced a 7% increase on energy requirements on ME for animals kept 516 masl higher. Further research is requiered to apply to other biological models.