Ocular echobiometry and head measurements in Jersey cattle from different age groups.

A longitudinal study was conducted to identify the morphological development of eyes and head of Jersey cattle at different ages. A total of 48 healthy Jersey cattle, 1 to 58 months of age, were included in the study. Ophthalmologic examinations were performed to identify healthy cattle to form the age groups: GI (1- to 11-month-old), GII (16- to 24-month-old) and GIII (25- to 58-month-old). The animals were physically restrained and examined by transcorneal ultrasound of both eyes; the axial length (AxL), corneal thickness (CO), lenticular thickness (L), depth of the anterior (AC) and vitreous (VC) chambers were evaluated. The cranial measurements obtained included the total, cranial, and nasal lengths and widths. Subsequently, the cephalic index (CI) was calculated. The AxL (GI: 2.83 cm; GII: 3.16 cm; GIII: 3.24 cm), AC (GI: 0.44 cm; GII: 0.53 cm; GIII: 0.53 cm), L (GI: 0.88 cm; GII: 1.01 cm; GIII: 1.04 cm) and VC (GI: 1.44 cm; GII: 1.55 cm; GIII: 1.59 cm) increased (p ≤ .001) according to age, but the CO (GI: 0.07 cm; GII: 0.08 cm; GIII: 0.08 cm) (p > .05) did not. The total length (GI: 30.83 cm; GII: 43.29 cm; GIII: 44.15 cm), cranial length (GI: 18.11 cm; GII: 23.82 cm; GIII: 22.69 cm), nasal length (GI: 12.72 cm; GII: 19.47 cm; GIII: 21.46 cm) and nasal width (GI: 26.22 cm; GII: 33.82 cm; GIII: 34.00 cm) increased (p < .001), and the CI (GI: 85.66 cm; GII: 78.15 cm; GIII: 77.02 cm) decreased (p < .001). The AxL correlated positively (p < .001) with the cranial length and width and negatively with the CI (p > .05). The ocular biometry of Jersey cattle correlates with their cranial measurements at different ages. With increasing age, the eyes and the head grow, establishing growth curves similar to those of other mammals.

Ultraviolet radiation induces dose-dependent pigment dispersion in crustacean chromatophores.

Pigment dispersion in chromatophores as a response to UV radiation was investigated in two species of crustaceans, the crab Chasmagnathus granulata and the shrimp Palaemonetes argentinus. Eyestalkless crabs and shrimps maintained on either a black or a white background were irradiated with different UV bands. In eyestalkless crabs the significant minimal effective dose inducing pigment dispersion was 0.42 J/cm(2) for UVA and 2.15 J/cm(2) for UVB. Maximal response was achieved with 10.0 J/cm(2) UVA and 8.6 J/cm(2) UVB. UVA was more effective than UVB in inducing pigment dispersion. Soon after UV exposure, melanophores once again reached the initial stage of pigment aggregation after 45 min. Aggregated erythrophores of shrimps adapted to a white background showed significant pigment dispersion with 2.5 J/cm(2) UVA and 0.29 J/cm(2) UVC. Dispersed erythrophores of shrimps adapted to a black background did not show any significant response to UVA, UVB or UVC radiation. UVB did not induce any significant pigment dispersion in shrimps adapted to either a white or a black background. As opposed to the tanning response, which only protects against future UV exposure, the pigment dispersion response could be an important agent protecting against the harmful effects of UV radiation exposure.

Effects of the parasite Probopyrus ringueleti (Isopoda) on glucose, glycogen and lipid concentration in starved Palaemonetes argentinus (Decapoda).

Effects of the branchial ectoparasite isopod Probopyrus ringueleti on the utilization of glucose, glycogen and total lipids on starved shrimp Palaemonetes argentinus were evaluated, as well as the isopod responses to host starvation. Shrimp were maintained for 12 d under laboratory conditions. Parasitized and unparasitized shrimp were starved for 15 d, and glucose, glycogen and total lipid concentrations were determined at 0, 24, 72, 168 and 360 h of starvation. During starvation, control animals (unparasitized) preferentially metabolized lipids and preserved their carbohydrate reserves. Parasitized shrimp had lower lipid concentrations than unparasitized shrimp, and preferentially metabolized carbohydrates. Bopyrids displayed a similar response, with glycogen depleted at the beginning of the starvation period followed by subsequent reestablishment. Our results demonstrated that bopyrids affect host energy allocation. The lower initial lipid concentration of parasitized shrimp suggested that the host is disadvantaged from both food deprivation and isopod nutritional demands. A possible dependency of P. ringueleti on the mechanisms that control host metabolic processes was also suggested.