Darko Grbeša

Blood metabolites and haematological indices of beef cattle fed rumen-protected methionine

U ovom radu su prikazani rezultati ispitivanja uticaja, u buragu nerazgradljivog, zasticenog (by-pass) metionina na neke vrednosti hematoloskih i biohemijskih parametara u krvi tovne junadi, ukljucujuci ukupne proteine, albumine, triacilglicerole, ukupni holesterol, glukozu, ureu, kreatinin, aktivnost alanin-aminotransferaze (ALT), aktivnost aspartat-aminotransferaze (AST), aktivnost gamaglutamil- transferaze (GGT), broj eritrocita (RBC), srednji volumen eritrocita (MCV), srednju vrednost hemoglobina eritrocita (MCH), raspodelu eritrocita po volumenu (RDW), koncentraciju hemoglobina (Hb), hematokrit (Hct), broj leukocita (WBC) i diferencijalnu krvnu sliku. Istraživanje je trajalo 94 dana i izvrseno je na 26 životinja podeljenih u dve jednake grupe, kontrolnu (C) i oglednu (E). Junad je hranjena livadskim senom i kukuruznom silažom uz dnevni dodatak 500 g krmne smese (35% CP) po grlu. Životinje iz grupe E su dnevno, po grlu, dobijale i 10 g DL-metionina zasticenog od razgradnje u buragu. Uzorci krvi su uzimani 1., 34., 68. i 94. dana ogleda. Nivo glukoze i ukupnog holesterola u plazmi grupe E je pokazivao tendenciju rasta prema kraju ogleda (P=0,065 odnosno P=0,064), dok je nivo uree imao tendenciju pada (P=0,082). Aktivnost ALT, kod životinja grupe E, je pokazivala 68. i 94. dana tendenciju porasta (P=0,127 odnosno P=0,104). Razlike u koncentraciji ukupnih proteina, albumina, triacilglicerola, kreatinina i aktivnosti AST i GGT između grupa nisu bile signifikanatne. Ovi rezultati ukazuju da bi suvisak metionina mogao da izazove porast nivoa glukagona u krvnoj plazmi.

In vitro digestibility of phenolics in grain of maize hybrids

Abstract The aim of this research was to determine the quantity of phenolic compounds in the grain of maize hybrids and their in vitro release in pig small intestine. Six maize hybrids belonging to the FAO maturity groups 200-600 were produced under the same agroclimate conditions. Phenolics were determined using Folin-Ciocalteu colorimetric method as gallic acid equivalents. The enzymatic digestion of phenolics was carried out using in vitro procedure for pigs mimicking digestion in stomach and small intestine. The concentration (mg/100g) of free (100.02-157.29), bound (973.41-1160.86) and total phenolics (1105.82-1293.38) varied (P<0.001) among hybrids. In addition, the digestibility of phenolics significantly differed among tested hybrids (P<0.001) and ranged from 37.09 to 45.46%. Content of phenolics in soluble fraction after digestion was higher (486.23 vs. 128.38 mg/100g) than the content of free phenolics suggesting that some amount of bound phenolics was released in small intestine.

Environmental and management effects on grain quality of maize hybrids

Maize yield and quality responses to N and plant populations were significantly affected by environmental conditions. However, hybrid-specific differences in grain protein and oil contents were consistent in all environments and regardless of contrasting N fertilization rates and plant populations, showing the importance of hybrid selection for Croatian farmers.

Effects of inclusion of maize silage in a diet based on grass silage on the intake, apparent digestibility and nitrogen retention in wether sheep

The objective of this experiment was to study the effects of interactions between grass silage (GS) dominated by orchardgrass (Dactylis glomerata L.) and maize silage (MS) (Zea mays L.) on ad libitum intake, digestibility and nitrogen retention in wether sheep. The GS in this experiment reflected the quality of GS produced on family farms in Croatia, while the MS used is frequently produced in seasons unfavourable for high quality MS production. The study consisted of four feeding treatments involving GS and MS alone, and GS and MS mixtures in ratios of 67:33 or 33:67 (DM basis), fed twice daily. Mean DM contents of GS and MS were 396 and 264 g/kg fresh weight, respectively. MS was much lower (P < 0.001) in crude protein (CP) (62 g/kg DM) than the GS (120 g/kg DM). GS contained larger (P < 0.001) quantities of neutral detergent fibre (NDF) and acid detergent fibre (ADF) than MS. In contrast, MS contained more (P < 0.001) non-structural carbohydrate than GS, as starch, which comprised 211 g/kg DM. Inclusion of MS in the diet (33% v. 67%) had positive linear effects on fresh matter voluntary intake (P < 0.05), CP and starch digestibility (P < 0.05), and N balance (P < 0.05). A positive associative effect of GS and MS was observed for DM, organic matter intake (quadratic, P < 0.05), N intake and N balance (quadratic, P < 0.01), while it was negative for ADF digestibility (quadratic, P < 0.05). It was concluded that positive interactions of GS and MS were due to a better balance of available energy and protein when the two forages were fed together. No positive associative responses were recorded for digestibility, probably due to higher passage rates of digesta with MS supplementation i.e. lower MS quality in terms of maize plant maturity at harvest.

Relation between endosperm and in vitro kinetic of starch digestibility in maize hybrids for broiler chickens

Abstract The objective of this study was to determine relationship between endosperm type of maize hybrids produced in Croatia and kinetic of starch digestibility provided by in vitro method. Proportion of endosperm type (horny and floury) were used to classify hybrids into dents or flints maize. Flints had less rapidly digestible starch than dents. Maize hybrid kernel endosperm characteristics could be used for prediction of digestibility kinetics of maize grain.

Intake and digestibility of sheep-fed alfalfa haylage supplemented with corn

Abstract: The objective of this study was to determine the effect of dry corn (DC) and fermented corn (FC) supplemented to alfalfa haylage (AH) (Medicago sativa L.) on feed intake, digestibility, and nitrogen (N) balance in wether sheep. The study consisted of five feeding treatments incorporating AH alone and AH supplemented with 5 or 10 g of DC (DC5 and DC10, respectively) or FC (FC5 and FC10, respectively) kg-1 body weight (BW) d-1 to Suffolk wethers. The DC5 and FC5 treatments were higher in acid detergent fibre (ADF) intake (P < 0.001), neutral detergent fibre (NDF) intake (P < 0.001), and N intake (P < 0.05) compared with the DC10 and FC10 treatments. Both energy sources (DC and FC) and supplemental levels (5 and 10 g kg-1 BW d-1) increased (P < 0.05) the digestibility of dry matter (DM) and organic matter (OM), and the digestibility of OM in DM (D value), and decreased the digestibility of ADF (P < 0.05). The DC10 and FC10 treatments had higher D values (P < 0.05) and reduced ADF digestibility values (P < 0.05) compared with the DC5 and FC5 treatments. The FC supplemented treatments had reduced N balances compared with DC treatments (P < 0.001). It was concluded that DC was a better supplement to AH than FC in terms of NDF intake, crude protein (CP) digestibility, and N balance. The main effect of increasing the level of starch supplementation to the diet was a reduced N and fibre intake, as well as N and fibre digestibility, but an increased D value.

Nitrogen Uptake and Utilization Efficiency of Maize Hybrids under High and Limited Nutrient Supply

Maize (Zea mays L.) genotypes wit It improved nitrogen utilization efficiency (NUE) are of interest to growers. Field experiments were conducted to evaluate the total N uptake in the aboveground biomass and NUE (kg grain per kg of N absorbed in the aboveground biomass). Four commercial hybrids of similar maturity ranking were grown under the high-N (200 kg N ha(-1)) and low-N (1100 kg N ha(-1)) fertilization rates over three years. Growing conditions significantly affected hybrid performance for NUE, which ranged from 42 kg grain kg N-1 in the low-yielding (dry) environment to 55 kg grain kg N-1 under higher yielding environment, When compared to the low-N rate, the average N uptake was by 32% higher at the high-N rate, whereas smaller differences occurred for the aboveground biomass (12%), grain yields (14%), stover N (28%) and grain N (13%) concentrations. Significant differences existed among tested hybrids for grain yield, aboveground biomass, grain and stover N concentration, N uptake and consequently NUE.Hairy vetch (Vicia villosa Roth) and crimson clover (Trifolium incarnatum L.) were evaluated as cover crops during two vegetation seasons in the Mediterranean and Continental area of Croatia. Better tolerance to low winter temperatures was observed for crimson clover. Higher plants (10 to 3 1 cm) before winter and in spring (67 to 117 cm) were measured for hairy vetch, while crimson clover had higher yields of fresh biomass (33.7 to 113.1 t ha(-1)). Concentrations of N (1.53 to 3.34%), P2O5 (0.55 to 1.04%) and K2O (2.02 to 5.32%) in plant tissue were higher for hairy vetch. However, due to higher yields of dry matter, crimson clover accumulated more N (105 to 239 kg ha(-1)), P2O5 (28 to 83 kg ha(-1)), and K2O (105 to 440 kg ha(-1)) than hairy vetch. According to our results crimson clover could be recommended as a cover crop in Mediterranean and Continental area of Croatia.

Estimating grass and grass silage degradation characteristics by in situ and in vitro gas production methods

Abstract Fermentation characteristics of grass and grass silage at different maturities were studied using in situ and in vitro gas production methods. In situ data determined difference between grass and silage. Degradable fraction decreased as grass matured while the undegradable fraction increased. Rate of degradation (kd) was slower for silage than fresh grass. Gas production method (GP) data showed that fermentation of degradable fraction was different between stage of maturity in both grass and silage. Other data did not show any difference with the exception for the rate of GP of soluble and undegradable fraction. The in situ degradation characteristics were estimated from GP characteristics. The degradable and undegradable fractions could be estimated by multiple relationships. Using the three-phases model for gas production kd and fermentable organic matter could be estimated from the same parameters. The only in situ parameter that could not be estimated with GP parameters was the soluble fraction. The GP method and the three phases model provided to be an alternative to the in situ method for animal feed evaluations.