Digestibility and energy content of Paulownia (Paulownia elongata S.Y.Hu) leaves

G. Ganchev1*, А. Ilchev1, А. Koleva2

1Department of Morphology, Physiology and Animal nutrition, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria 2Department of Technology of cereals, fodder, bread and confectionary products, Technological Faculty, University of Food Technology, 4000 Plovdiv, Bulgaria

(Manuscript received 5 July 2019; accepted for publication 3 September 2019)

Abstract. The aim of the study was to determine the digestibility and energy content of Paulownia elongata S.Y.Hu leaves after leaf fall. Leaves together with petioles were dried at room temperature and milled with a roughage mill before feeding to animals. A classical digestion trial was performed, with three rams weighing 55.4kg on average, by determining the chemical composition of consumed feed, feed leftovers and excreted faeces. Digestibility was evaluated as difference in the amount of ingested nutrients and nutrients excreted with faeces and it was determined to be 50.72, 52.08, 31.63, 54.09, 55.15 and 56.06% for dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE), crude fibre (CF) and nitrogen-free extract (NFE). The energy value for ruminants calculated on the basis of chemical composition and established digestibility was 8.29 MJ digestible energy (DE)/kg DM, 6.55 MJ metabolizable energy (ME)/ kg DM, 0.59 feed units for milk (FUM)/kg DM and 0.52 feed units for growth (FUG)/kg DM.

In vivo digestibility of cereal-based diets supplemented with sunflower vs. rapeseed meal

M. Yossifov, L. Kozelov
Abstract. Two experiments were conducted to investigate effects of rapeseed meal (RSM) vs. sunflower meal (SFM) as a protein source at cereal-based isonitrigenous (at 16 % CP), iso-caloric at gross energy 18 kcal/kg and net (FUG=1) energy diets for fattening lambs. Four wethers (Gygay breed) were used to evaluate the diets’ apparent total tract digestibility (dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE), crude fibres (CF), nitrogen free extractives (NFE) and ash) and coefficients (Cd) were used to calculate the diets’ feeding value. Two diets were used: conrol diet (CD) with SFM and experimental diet (ED) with RSM. The results indicated that feeding RSM tended to increase Cd OM (p=0.1), Cd CP (p=0.4), Cd EE (p=0.5) and Cd NFE (p=0.1). The differences were significant at Cd DM (p<0.05), Cd CF (p<0.05) and Cd ash (p<0.001). According to the calculation analysis, diet supplementation with RSM benefits total digestible nutrients (TDN), raised energy values (gross energy, digestible energy and net energy) and improved protein feeding values (protein trully digestible in small intestines (PDI) and balance of protein in rumen (BPR)). Therefore, it’s concluded that, substitution of SFM with RSM in cerealbased ruminant diets significantly (p<0.05) increased in vivo diet digestibility, raised (11 %) TDN and improved its energy and protein feeding value.


Use of brewer’s grains for feeding of lambs

A. Kirilov, K. Ivanov
Abstract. In production of beer, bio-ethanol or bio-diesel from grain or oil-bearing seeds by-products are obtained having good forage characteristics. The byproducts from brewing and distilling industry, which are rich in protein and are successfully used as protein sources in the rations for ruminant animals, are of interest to the farmers. The objective of this study was to compare the effect of substitution of 50% of the protein of sunflower meal in the compound feed by protein from brewer’s grains, preserved and fresh, or from rapeseed meal in feeding of lambs. For that purpose an experiment was carried out with 40 lambs of initial live weight of 27 kg from the Pleven Blackface sheep breed divided into 4 groups. On average for the experimental period the obtained daily weight gain was 206 g for the lambs from І group fed with sunflower meal and 205 g, 197 g and 253 g for ІІ, ІІІ and ІV group respectively, where 50% of the protein of sunflower meal was substituted by preserved brewer’s grains, rapeseed expeller and fresh brewer’s grains. It was concluded that the substitution of 50% of the protein of sunflower meal by such one from brewer’s grains or rapeseed expeller did not influence negatively the weight gain and feed consumption in feeding of lambs.


Age-related changes in mineral retention and excretion in starter and finisher pigs diets with and without exogenous phytase

А. Ilchev, G. Gаnchev, S. Chobanova, D. Kanakov, P. Petkov, I. Nikiforov

Five balance feeding trials were performed to evaluate age-related changes in nitrogen, phosphorus and calcium utilization in growing and fattening male castrated DanBred hybrid pigs. Two commercial phytase preparations were used: Optiphos and Natuphos at a dose of 0.01 %. It was found out that with age, the amount of dietary nitrogen intake and nitrogen output in urine increased statistically significantly (P<0,05). The total nitrogen output was also higher. The retention of nitrogen decreased substantially with age. The supplementation of rations with phytase did not alter this tendency. Phytase added to feed improved phosphorus absorption by 28-34 % and reduced its total output by 38-45 %. The digestibility of calcium in pigs decreased with age, whereas its output in faeces became higher. There was no statistically significant difference between the effects of Optiphos and Natuphos


Effect of dietary exogenous phytase supplementation in growing and fattening pigs

Three balance feeding trials were performed with 3 groups male castrated pigs during the starter, grower and finisher periods. The animals were housed in specially designs individual cages that allowed for separate collection of urine and faeces. Each trial comprised 5 days preliminary and 5 days experimental period. Pigs were fed compound feeds according to their genotype and age. The first groups received compound feed without exogenous phytase. The feed of the second group was supplemented with the Bulgarian enzyme preparations Optiphos at 0.01 %, аnd the feed of group III – with the same amount of the enzyme preparation Natuphos. The results showed that the inclusion of exogenous phytase in compound feeds for pigs permitted to decrease the amounts of used dicalcium phosphtate by 3 to 7 times. This reduced the amount of total dietary phosphorus by 27-30 % and the cost of feeds. The utilization of phytase improved the absorption of phosphorus by 28-34 % and decreased its total output by 38-45 %, without any effect upon nitrogen retention. The performed trials did not shown any significant difference between the effects of both exogenous phytases used: Optiphos and Natuphos.

Effect of dietary exogenous phytase supplementation in growing and fattening pigs

А. Ilchev