Distribution of 15N-chlorocholine chloride in eggs of laying hens

The distribution of Chlorocholine chloride (CCC) in the eggs of laying hens was studied using 15N-CCC. Twelve layers (37 weeks old) were divided into four groups and used in this study consisting of three feeding phases. In phase one (7 days), all the hens received a CCC-free diet [165 g CP/kg dry matter (DM); 11.58 MJ ME/kg DM]. In phase two (11 days), four levels of 15N-CCC: 0, 5, 50 and 250 ppm were added to the respective diets, while in phase three (7 days), CCC-free feed was again offered. Egg samples were taken and the 15N content of egg yolk and albumin were determined. At the end of phase two, there was a significant (p < 0.05) increase in 15N content in egg yolk from hens fed the 50 and 250 ppm CCC diets and in albumin from hens fed the 250 ppm CCC diet. The estimated 15N-CCC residue was 1.71, 6.64, 28.80 ppm in egg yolk and 1.58, 1.08 and 4.50 ppm in albumin from hens fed 5, 50 and 250 ppm CCC, respectively. The CCC residue, from quantitative analysis ranged from 0.21 to 0.93 and 0.93 to 2.43 ppm in yolk of hens fed 50 and 250 ppm CCC, respectively, whereas a range of 0.40-1.46 ppm, was found in the albumin of hens fed 250 ppm. The difference in measured CCC in yolk and albumin and that estimated from 15N-CCC could have been due to breakdown products of 15N-CCC. Seven days after withdrawal of 15N-CCC, the estimated 15N-CCC residue in egg yolk decreased to 0.43, 2.45 and 15.59 ppm, on 5, 50 and 250 ppm CCC dietary treatments, respectively, and to 2.46 ppm in albumin from hens fed 250 ppm CCC. The higher increase in 15N content could have been due to a higher incorporation of 15N-CCC into yolk than albumin during the process of rapid yolk deposition. This experiment showed that consumed CCC is distributed both into yolk and albumin in a dose dependent manner and that CCC is metabolized in laying hens. However, the level of CCC in the diet which could lead to accumulation of detectable CCC levels in eggs as observed in this study, is much higher than the established maximum residual limits in grains.     

Reproductive performance of female rainbow trout Oncorhynchus mykiss (Walbaum) kept under water temperatures and photoperiods of 13° and 51°N latitude

At Doi Inthanon Fisheries Research Unit (DIFRU), Thailand (13°N), rainbow trout were exposed to natural (13°N) and artificial (51°N) photoperiods, and natural water (NW) temperatures and cooled water (CW) 8 months before first spawning. In group I (51°N, CW), water temperatures of 18°C were never reached. In group II (51°N, NW) and group III (13°N, NW), the mean water temperatures in May exceeded 20°C, and 19°C in June and July. Eggs from 94% of all females in group I were obtained before January. This percentage diminished to 84% and 68% in groups II and III. The weight of the spawners and the size of the eggs were significantly lower in group III than in the other groups. No significant differences were observed for egg number per kg body weight of spawners between the groups. The mean fertilization rate of eggs was the highest, with 71%, in group I, and the lowest, with 50%, in group II. For hatching rates, on average 27%, 24% and 30% in groups I, II and III, respectively, differences were not significant. In group III, 37% of all batches reached fertilization rates above 80% and 16% of egg batches showed hatching rates of more than 60%.     

Effect of Imbibition/Dehydration Treatments on Germination and Seedling Growth of Maize (Zest mays) Cultivars

Caryopses of maize cultivars of different origin were used for germination experiments. During the phase of germination the moisture supply was changed, so that after an initial soaking the kernels were desiccated. Finally the inbibition/dehydration treatments were followed by soaking the kernels to allow seedling growth. This experimental design mirrors natural conditions (in subtropical/tropical climates) which are characterized by short rain and drought periods during the sowing of maize.
The maize cultivars were chosen from German and Thai hybrids and open pollinated varieties. In the treatments, the initial imbibitions were 24, 36, 48 and 60 hours; the dehydration periods were 24 and 48 hours. Percentage of regermination, radicle length, number of mesocotyl roots, root and shoot dry weights, were measured as indicative features for evaluation of the resistance against changing moisture content of the kernels during the germination phase.
The results show, that a duration of 36 hours of imbibition describes in general the dehydration-insensitive phase. Dehydration after imbibition periods of 24 (or 48) hours very often lead to a growth acceleration in the following germination after the kernels are imbibed again. If the germination proceeds for a longer period, as tested for 48 or 60 hours, all maize cultivars will show detrimental effects of dehydration on germination and seedling growth. However, there are distinct differences within the material tested, the Thai cultivars being more resistant than German hybrids. The reactions may be explained by differences in the rate of development during the first phase of germination. Slowly germinating genotypes probably pass later the border line from the insensitive to the sensitive phase against dehydration after an initial imbibition of the kernels.