Histochemical research of enzymes involved in cellular digestion in the digestive tract of tub gurnard, Chelidonichthys lucerna.

The tub gurnard Chelidonichthys lucerna (Linnaeus, 1758), Triglidae, is an opportunistic, demersal carnivorous fish. Data on the digestive enzymes of tub gurnard have not been reported in the literature. Therefore, the aim of this research was to investigate the distribution and intensity of alkaline phosphatase, acid phosphatase, non-specific esterase, and aminopeptidase in the digestive tract of tub gurnard. To investigate data about those enzymes tissue samples of the esophagus, anterior and posterior part of the stomach, pyloric caeca, anterior, middle and posterior part of the intestine proper, and rectum were taken. Azo-coupling methods were used to detect the enzymatic reactions. The intensities of the reactions were measured using ImageJ software. Alkaline phosphatase, acid phosphatase, and non-specific esterase activities were found in all parts of the digestive tract. The brush border of the pyloric caeca and intestine proper were the main sites of alkaline phosphatase reaction, with intensity decreasing toward the posterior parts of the digestive tract. The high intensities of acid phosphatase were found in the epithelium of the anterior part of the stomach, pyloric caeca, anterior part of the intestine proper, and in the rectum. The intensity of non-specific esterase was mainly increased from the anterior to the posterior parts of the digestive tract. Aminopeptidase activity was found in the esophagus, pyloric caeca, and intestine proper. Our results suggest that the entire digestive tract of the tub gurnard is involved in the digestion and absorption of dietary components.

Prediction of reproductive performance of ewes based on the early production data, ewe birth rank, dam age, and dam birth rank.

This research aimed to analyze whether ewes' total reproductive performance up to the fourth year of life (RP4) can be predicted based on the data available at an early stage of a ewe's productive life. The RP4 of 133 Romanov ewes was measured in terms of the total number of lambs born per ewe (TNLE) and total birth weight of lambs per ewe (TBLE). Multiple regression was used to analyze whether early reproductive performance indicators (first litter size - FLS, age at first lambing - AFL, first lambing interval - FLI), ewe birth rank, dam age, and dam birth rank can be used as the predictors of RP4. Predicted R 2 and 95 % prediction intervals were used as indicators of the precision of prediction. Average TNLE and TBLE at the end of fourth year of ewe life were 11.84 lambs and 37.96 kg, respectively. FLS and FLI significantly ( P < 0.05 ) influenced TNLE and TBLE, while AFL was not a significant ( P > 0.05 ) variable. Ewes with shorter FLI had significantly ( P < 0.05 ) higher TNLE (10.94 lambs) and TBLE (36.17 kg) than ewes with long FLI (TNLE  =  9.12 lambs and TBLE  =  28.05 kg). R 2 predicted for TNLE and TBLE was 7.54 % and 11.49 %, respectively. The ewe's birth rank and the dam's birth rank significantly ( P < 0.05 ) influenced TNLE and TBLE. Ewes born as singletons and ewes from singleton-born dams had significantly ( P < 0.05 ) lower TNLE and TBLE than ewes born as triplets and ewes from triplet-born dams. R 2 predicted for TNLE was 16.76 %, and 25.69 % for TBLE. FLS and FLI are better predictors of RP4 than AFL. The birth rank of ewe and dam also proved significant predictors of RP4. For both sets of predictors (early reproductive indicators and birth rank data), low values of R 2 predicted indicate that precise prediction of RP4 cannot be made.