Josip Novoselec

Changes of thyroid hormones concentration in blood of sheep depending on age and reproductive status

Abstract The influence of the reproductive status was tested in the blood serum of 30 sheep (10 pregnant sheep on the 15th day prior to lambing, 10 lactating sheep on the 20th day of the lactation and 10 non-pregnant sheep). The influence of age was determined in the blood serum of 20 sheep and 20 lambs. Analysis of the impact of age in sheep and lamb on the concentration of thyroid hormones showed that 30-day old lambs had significantly higher (P<0.01) concentration of T3 and T4 compared to the other age categories of sheep. At the same time, 100-day old lambs had significantly higher concentration of T4 if compared to the 1 and 3-year old sheep. Referring to the reproductive status, there was significantly lower (P<0.01) concentration of T3 determined in the blood of lactating sheep than of non-pregnant and pregnant sheep. These findings point out unsatisfactory energy supply in the older sheep, sheep during late pregnancy and sheep at the beginning of lactation.

Influence of different selenium sources on performance, blood and meat selenium content of fattening lambs

Abstract An investigation was conducted to evaluate the bioavailability of different Se sources on fattening lambs. Forty-eight lambs, divided in 3 groups, were ad libitum fed the same diet without Se addition (control, C), or with a supply of 0.03% sodium selenite (IS) or 0.03% of organic selenium (OS; Sel-PlexTM). Growth performances were not affected by treatment. With respect to C, OS significantly increased Se content of blood (P<0.01), liver (P<0.01) and GSH-Px enzyme activity (P<0.01). OS also significantly increased blood (P<0.01) and liver (P<0.05) Se content with respect to IS. It was concluded that Se in organic form had a better bioavailability compared to the inorganic form.

Concentration of selenium in soil, pasture, blood and wool of sheep

Investigations have been conducted on Slavonia during a threeyear period on six locations, two per each year during June (in the firstyear = Vinkovci and Beli Manastir; in the second year = Valpovo andDjakovo; in the third year Slatina and Donji Miholjac). Six samples fromthe soil, pasture and sheep wool, as well as 15 sheep blood samplesweretakenfromeachlocality.Therewasadeficitofseleniumcontentinthe soil on four locations in the second and third year (0.18; 0.14; 0.10and 0.07 mg/kg) and an adequate content on locations Vinkovci andBeliManastirinthefirstyear(0.98and0.71mg/kg).ThelocalityValpovowas characterized by the highest selenium concentration in pasture,blood and wool of sheep, as well as by the lowest blood enzymesactivities (ALT, AST, CK, LDH) when compared to other locations.Selenium concentration in pasture was under the critical range on alllocations (from 0.006 to 0.03 mg/kg DM), except the locality Valpovo inthe second year (0.05 mg/kg DM). Serum selenium concentrations(from 0.035 to 0.082 mg/L) on all locations were below the adequaterange for adult sheep and differed among locations. Activities ofenzymes in the blood of sheep (AST: 3.59, CK: 4.93 and LDH:6.87 µkat/L) showed severe selenium deficiency. Seleniumconcentrations in the wool were under the critical level on all locations(from <0.0002 to 0.06 mg/kg). The results regarding selenium in woolshowed that, apart from blood selenium and activities of plasmaenzymes (AST, CK, LDH), wool should also be taken in account as aselenium status indicator.Key words: blood, enzyme blood activity, selenium, sheep, soil,pasture, wool

Status of selenium and correlation with blood GSH-Px in goats and their kids in organic breeding fed with different levels of organic selenium

The aim of this research was to determine how the supplement of organic selenium (OS) in the diet at different concentrations reflects on the content of blood Se and GSH-Px activity and their correlation in goats and their kids in organic breeding. The study included 24 Alpine goat breeds during lactation and their kids. Goats were divided into three groups depending on dietary treatments. Goats were fed with the cereals mixture 1 kg/per day in control group (C). OS supplied as selenised yeast in the first experimental group (E-I) 0.015% and in the second experimental group (E-II) 0.030% in cereals mixture. The addition of OS significantly (P<0.01) increased blood Se of goats and kids in E-I and E- II groups in relation to C group and higher (P<0.05) in E-II in comparison with the E-I group. Concentrations of Se followed by GSH-Px activity, and were higher in the EI and E-II groups in comparison with C group. In the blood of suckling kids has determined higher (P<0.01) GSH-Px activity in E-I and E-II groups in relation to C group. It was also determined higher GSH-Px in the blood of kids E-II group compared to the EI group. Significant correlations was found between Se levels and GSH-Px activity in goats and kids, but were significant only in the goats of E-II group. The results obtained concentration of Se and GSH- Px in the blood goats and kids showed the validity of adding OS into food in organic breeding.

Changes in macroelements, trace elements, heavy metal concentrations and chemical composition in milk of Croatian spotted goats during different lactation stages

The research was conducted on days 60, 90, 120 and 150 during the lactation with the aim to determine the effect of lactation stage on the concentration of crucial elements and chemical composition in Croatian spotted goats’ milk. Milk yield significantly decreased (from 1.15 to 0.76 kg/day), while the concentration of Ca, Mg, P, Zn and Mo in the milk of the goats significantly increased during lactation. The concentrations of Cr, Cd and Pb in milk were very low, with no significant deviations during lactation. The quality of milk from Croatian spotted goats is adequate compared with other breeds in the surrounding area of Croatia.