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P Constantin

Publications and source records attributed to P Constantin.

18 recordsLinked to original sources
PubMed2000

Early locomotor behaviour in genetic stocks of chickens with different growth rates.

Reduction in exercise increases the occurrence of lameness in meat-type chickens. Locomotor activity is dramatically reduced during the finishing period in chickens from fast-growing genetic types compared to slow-growing genetic types, but it is not known whether this difference is already present during the starting period and may be influenced by genetic factors. In order to define the effect of genetic origin on early locomotor behaviour, exercise was compared from 1 to 22 days of age in two meat-type chicken stocks differing in growth rate: male broilers (B) which grow fast and are often lame, and male "label rouge" chickens (L) which grow slowly and are rarely lame.Time budget (lying, standing, drinking, eating, walking) was measured by scanning in six repetitions of five birds (density=2.5 birds/m(2)) at 1, 8, 15 and 17 days of age. Standing bouts were analysed by focal sampling at 2-3, 6-7, 13-14 and 20-21 days of age.B chicks spent less time standing than L chicks at 15 days of age (B=13+/-2%, L=24+/-1%, P<0.01) and 17 days of age, and spent more time lying at 17 days of age (B=73+/-3%, L=60+/-4%, P<0.05).The major part (74%) of the total active time observed by focal sampling was linked to feeding activity. At 2 and 3 days, the activity of B chicks was half that of L chicks during standing bouts (duration of walking per bout: 19+/-4 s for B; 45+/-4 s for L, P<0.05). The activity observed by focal sampling during non-feeding bouts at 20-21 days was significantly correlated with the corresponding data recorded at 2-3 days in the same chicks in the B stock but not in the L stock.We concluded that (1) both B and L genetic stocks have the same overall activity during the first 3 days of age (scanning) but they exhibit different organisation and composition of standing bouts (focal sampling). (2) Genetic factors are probably involved in the expression of locomotor behaviour in very young chicks. (3) The correlations between the levels of activity at early and later ages suggest that selection of young mobile broiler chicks might increase activity at a later age and might therefore reduce the occurrence of leg abnormalities.

Journal Article↗
PubMed1999

Early bone growth in chickens genetically selected for a high and low growth rate.

Male chickens from lines divergently selected for fast (FGL) and slow (SGL) growth were compared for the growth of cortical bone. Morphology, histomorphometric, compositional and biomechanical properties of the tibiotarsi were analysed in both lines at 1, 8, 15 and 22 d of age. Tibial morphology (length, volume, cross-section and diameters) was similar in FGL and SGL chickens when compared at an equal body weight. Cortical area was also similar in both lines at an equal body weight but cortex porosity was higher in FGL. Tibial mineral density (ash:volume) was higher in FGL than in SGL at hatching and at 8 d of age. Biomechanical properties were lower in SGL than in FGL at 8 d of age, but then became higher in this line when compared at equal body weight. The very slow growth rate in SGL did not modify bone size when chickens were compared at equal body weight. Bone quality was modified in various ways: in SGL bone structure was strengthened by a lower porosity of the cortex while bone tissue was less mineralized up to 22 d of age. In both lines, cortical growth was slower than in commercial cross-breeds and bone quality (structure and composition) was improved compared to broilers.

Aging↗
PubMed1998

Reducing growth rate of broiler chickens with a low energy diet does not improve cortical bone quality.

1. Reducing growth rate is often supposed to allow better skeletal development and improve bone quality. In order to test this assumption, flocks of broiler chickens fed on a diet containing 13.31 MJ ME/kg (H) were compared with flocks in which the growth rate was reduced by feeding birds with a low energy diet (L, 9.62 MJ ME/kg). 2. Bone growth was studied in 2 experiments in order to identify any changes in bone tissue of slow-growing chickens that might explain why they are less predisposed to varus-valgus deformities (3.1% vs 19.9%). 3. In experiment 1, the morphology, composition and histomorphometry of the tibiotarsi were analysed in both groups at 1, 12, 26, 42 and 46 d of age. Tibial variables (weight, volume, length, cortex size and structure, dry content and ash percentage) were always reduced in slow-growing birds except at 42 d of age, when tibial weight and cortex areas were similar in both groups. 4. Every variable was similar in both groups, or even higher in H birds, when chickens were compared at similar body weight, suggesting that the low growth rate did not improve bone quantity or quality of the tibiae. 5. In experiment 2, the composition of the tibiotarsi was compared every 2 days during the first week and twice a week until 36 d of age, in H and L birds. Weight and composition of the tibiotarsi did not differ between groups when compared at equal body weight, as also shown in experiment 1. 6. The reduced occurrence of varus-valgus deformities in slow-growing chicks cannot be related to an improvement in the structure and the composition of their bone tissue.

Animal Feed↗
PubMed1996

Sex differences in bone growth of broiler chickens.

Females are often supposed to have a lighter skeleton than males, even in avian domestic species. However, in broiler chickens, females are less susceptible to bone deformities than males. In order to better understand these conflicting facts, male and female broilers were compared for the growth of cortical bone. Morphology, histomorphometry, composition and biomechanical properties of the tibiotarsi were analysed in both sexes at 1, 12, 26 and 42 days of age. The quantity of bone tissue of the tibiotarsus (weight, volume, diameter of the diaphysis, area of the cortex) was smaller in females, although the occurrence of varus-valgus deformations of the intertarsal joint was largely reduced in female chickens (8.8% versus 19.9% in males at 42 days of age). The tibia became significantly lighter in females from 26 d of age. Differences in tibia length and volume became significant at 42 d of age only, while cross-sections of the diaphysis were smaller in females from the hatching, leading to thinner bones in females. The percentage of dry matter of tibiae was higher in females from hatching. From 12 days old, tibiotarsi of females tended to be less porous and were more mineralized (higher ash/dry matter ratio). In females, mineralization proceeded at a higher rate (MAR) until 26 d of age and MAR became higher in males afterwards. The stiffness of the tibia diaphysis was similar in males and females all along the growth. In conclusion, the growth of cortical bone is very different in male and female broilers. In female broilers, the thinness of bone diaphysis is counter-balanced by modifications in the composition of the matrix and in the porosity of the cortex, leading to equal biomechanical characteristics of tibiotarsi in both sexes.

Aging↗
PubMedDate not supplied

[Periodontal diseases with Entamoeba gingivalis].

At the beginning of our century Entamoeba gingivalis was considered to be a pathogenic bacteria, capable to induce parodontal lesions. Later on it was also found in healthy persons, and the germ was less interesting from the medical view-point. In the present study the authors report their findings concerning E. gingivalis in 135 patients with various stomatological affections including: dental caries, parodontopathies, pulpitis, gangrene, ulcero-necrotic stomatitis etc. The study was started following the discovery of the amoeba in the gingival exsudate of a male aged 19 years with chronic superficial marginal parodontopathy, who, after a treatment with metronidazol, was cured. Entamoeba gingivalis belongs to the Rhizopoda class, together with E. dysenteriae, and E. coli, but, in contrast with these strains it does not have resistance forms (cysts). Oral amoeba were evidenced in 18 out of 78 patients with parodontal lesions (23.07%), in the gingival exsudate, the purulent secretion from parodontal pouches, in the dental tartar, the alveolar fluid following extraction etc. In 117 students from the Faculty of Stomatology, and in 57 patients with various other stomatological affections these germs were not found in any of the abovementioned products. Microscopic examination of fresh preparations, and of Giemsa-stained smears was the main method for the detection of the amoeba. The etiopathogenic role of E. gingivalis is re-examined in discussions regarding certain parodontopathies.

Adult↗