EFFECT OF PROTEIN LEVEL ON GROWTH INTENSITY AND DIGESTIBILITY OF NUTRIENTS IN FATTENED CROSSBRED PIGS

G. Yordanova, R. Nedeva, K. Eneva, A. Apostolov

Abstract: At the Agricultural Institute – Shumen was carried out a scientific economic experiment with fattened pigs from the cross ♀Danube White (DW) x (English Landrace (EL) х Pietren (P)) х ♂Danish Landrace (DL). The animals were divided into two groups of 18 or a total of 36 pigs. Experience began at 29.294–29.278 kg live weight and ended at 100.706–102.167 kg. The experiment was conducted in two sub-periods – first from 30 to 60 kg live weight and second from 60 kg to end of experiment. In group II, the crude protein level was increased by 2 percentage points (from 17.0–15.5% to 19.0–17.5%), respectively, and higher was the level of amino acids in the compound feeds. At the end of the fattening of the animals, the lean meat content was determined in vivo. A physiological trial for digestibility of nutrients was performed with two groups of 3 male castrated
pigs with 67.000 kg live weight. Pigs were housed in dedicated cells. The digestibility was calculated for each animal individually, separately for each nutrient as the difference between the feed intake and the faeces. The results of the experiments showed that animals fed with compound feed containing 19.0–17.5% protein achieved a higher average daily growth (by 10.60%, p ≤ 0.001) and a lower feed conversion ratio (by 10.84%, p ≤ 0.001) compared to fed fodder with a protein content of 17.0–15.5%. A tendency was observed for the dorsal fat thickness for lower values (by 9.94% – x1 and 5.61% – x2) in animals receiving compound feed with a higher protein content and a higher coefficient of digestibility of fibers, fats, minerals and calcium by 25.58%, 23.28%, 16.68% and 12.40%, respectively, in the same group of pigs.

Keywords: compound feed; digestibility; fattened pigs

Date published: 2018-05-28