Effects of manganese glycine on eggshell quality, eggshell ultrastructure, and elemental deposition in aged laying hens.

Poor eggshell quality of eggs laid by aged laying hens is the major problem affecting the length of the rearing period in the laying hen industry. Trace elements are required and play vital roles in the eggshell quality of laying hens. Appropriate dose of organic microelements is environmentally friendly and sufficient to satisfy the needs of hens because of their greater bioavailability and lower excretion than inorganic forms. The aim of this experiment was to investigate the effects of manganese (Mn) glycine (MG) on eggshell quality, elemental deposition, and eggshell ultrastructure in aged laying hens. A total of 720 Hy-Line Brown hens 70 weeks old were assigned equally to four groups with six replicates of 30 birds each. The hens were fed basal diets (without Mn supplementation) supplemented with 120 mg/kg of Mn from manganese sulfate monohydrate (MSM), or 40, 80, or 120 mg/kg Mn from MG for 12 weeks. Dietary supplementation with 80 mg/kg Mn from MG resulted in the greatest eggshell strength after 6 weeks of treatment (P = 0.047), and in greater eggshell strength than observed in the MSM control after 12 weeks of treatment (P = 0.025). After 12 weeks of treatment, the eggs of hens in the MG groups showed lower mammillary layer thickness in the blunt end, equator, and acute end than observed in the MSM control group (P < 0.001). With the exception of the blunt ends of eggs from hens in the 120 mg/kg MG group, the eggs of hens in the MG groups, compared with the MSM control group, exhibited a lower mammillary layer ratio, and greater palisade layer ratio and effective layer ratio in the blunt end, equator, and acute end (P < 0.001). Dietary supplementation with 80 mg/kg Mn from MG, compared with the MSM control and 40 and 120 mg/kg MG, resulted in the greatest palisade layer thickness and effective layer thickness, and the lowest mammillary layer thickness in the equator (P < 0.001, P = 0.001, P < 0.001, respectively). Furthermore, supplementation with 80 mg/kg Mn from MG exhibited the greatest ratio of the palisade layer and effective layer, and the lowest mammillary layer ratio in the blunt end and equator (all P < 0.001). The Mn content of eggshells in hens-fed diets supplemented with 80 and 120 mg/kg Mn from MG was greater than that in the MSM control and 40 mg/kg MG groups (P = 0.035). Dietary supplementation with 80 or 120 mg/kg Mn from MG resulted in greater tibia Mn content than observed in the 40 mg/kg MG group (P = 0.019), and greater yolk Mn content than observed in the 40 mg/kg MG and MSM control groups (P = 0.018). In conclusion, dietary supplementation with 80 mg/kg Mn from MG, compared with the MSM control (120 mg/kg Mn), may increase the deposition efficiency of Mn, alter eggshell elemental composition, improve eggshell ultrastructure, and enhance eggshell strength in aged laying hens.

The infection status of anisakid larvae in marine fish and cephalopods from the Bohai Sea, China and their taxonomical consideration.

The infection status of anisakid larvae was examined in 290 marine fish of 25 species and in 108 cephalopods of 3 species purchased in Bayuquan region, Yingko city nearby the coast of the Bohai Sea from may to August 1992. A total of 7,327 larvae were collected from 156 fish of 19 species and 8 squids of one species. The 3rd-stage larvae of Anisakis simplex were collected from 121 fish (63.4%) of 15 species (N = 191) and from 8 squids (14.8%) of one species (N = 54), and they were total, 5,992 (81.8%). Out of remaining 1,335 larvae, 154 (2.1%) were classified as Thynnascaris type B from 23 fish of 4 species, 1,013 (13.8%) as Thynnascaris type C from 79 fish of 13 species. 164 (2.2%) as Hysterothylacium China type V from 20 fish of 4 species, 3 (0.04%) as Raphidascaris from 3 fish of 2 species and one was Pseudoterranova decipiens larva.