A group of 32 healthy men (M) divided into three different age groups, i.e. M20 years [mean 21 (SD 1); n = 12], M40 [mean 40 (SD 2); n = 10] and M70 [mean 71 (SD 5); n = 10] volunteered as subjects for examination of maximal and explosive force production of leg extensor muscles in both isometric and dynamic actions (squat jump, SJ and counter movement jump, CMJ, and standing long-jump, SLJ). The balance test was performed on a force platform in both isometric and dynamic actions. Maximal bilateral isometric force value in M70 was lower (P < 0.001) than in M40 and as much as 46% lower (P < 0.001) than that recorded in M20 (P < 0.001). The maximal rate of force development (RFD) on the force-time curve was in M70 lower (P < 0.001) than in M40 and as much as 64% lower than in M20. The heights in SJ and CMJ and the distance in SLJ in M70 were lower (P < 0.001) than in M40 and M20 (P < 0.001). In response to modifications of the visual surroundings the older subjects were 24%-47% (P < 0.05 and P < 0.001) slower in their response time in reaching the lit centre (TT) and remained 20%-34% (P < 0.001) less time inside the centre (TC) from the overall time of lighting than M40 and M20, respectively. In both older groups the individual values of isometric RFD correlated significantly (P < 0.05) with the individual balance values of TT and TC. The present results would suggest that the capacity for explosive force production declines drastically with increasing age, even more than maximal muscle strength. Aging may also lead to impaired balance with a decrease in event detection and speed of postural adjustments. The decreased ability to develop force rapidly in older people seems to be associated with a lower capacity for neuromuscular response in controlling postural sway.

Immature gilthead sea bream (Sparus aurata L.) with a mean initial weight of 25.6 g were reared over 11 months to market size under di¡erent photoperiods: 16L:8D; 24L:0D and a control. Di¡erences in ¢nal mean weight were signi¢cant between the three treatments (Po0.001): 16L:8D, 465.0 g; 24L:0D, 445.9 g; control, 402.6 g. Fish from the 24L:0D consumed most while 16L:8D ¢sh converted it most e⁄ciently. The lipid content of ¢llets was lower (Po0.05) for the 24L:0D (5.37 AE 0.16 g100 g À1 of ¢llet) than for the control (6.02 AE 0.12 g), and the moisture content lower for the control than for either treatment groups. Skin luminosity (L Ã ) was directly related to the number of hours of light exposure.

No abstract

Tinerfeñ a breed goats were assigned to 2 experimental herds and milked once (n = 28) or twice (n = 24) daily to study correlations between udder morphology, milk yield, and milking ability during the middle stage of the first lactation. Pearson correlation coefficients were significantly higher between yield and measures of udder globulousness (udder volume, r = 0.79 and r = 0.59; perimeter of insertion of the udder, r = 0.47 and r = 0.37; distance between teats, r = 0.77 and r = 0.28, for goats milked once and twice daily, respectively) than for length parameters (cistern floor distance, r = 0.40 and r = -0.29; udder depth, r = -0.20 and r = 0.20). The globulousness of the udder was correlated with easier milking ability, as shown by milk fractioning (r = 0.49 to 0.70) and milk flow measures (r = 0.32 to 0.49). The results showed that the globulousness of the udder is more important than length measurements in assessing milk yield and milking ability.

Gilthead sea bream (Sparus aurata L) pass through the period of sexual maturation while being intensively reared for commercial purposes. This process affects growth and food conversion efficiency. In an attempt to reduce this problem several lighting regimes have been utilized which impede gonad development by increasing the length of the day. A four hour increase in natural day length three months before reaching sexual maturation in fish of 390 g, improves growth in comparison to the control by about 15% (means SD of 606.2 ± 10.6 and 526.5 ± 12.7 g, respectively) towards the end of the natural reproductive season. However, these differences are subsequently compensated since the sexual maturation process is only delayed (rather than being permanently halted). The manipulated groups reached maturity and then stopped growing between three and four months after the control groups. For this reason, it would appear advantageous to manipulate sexual maturation through photoperiod alteration in those groups which go to market either during or towards the end of the reproductive season since greater fish weights will be achieved in addition to an improved food efficiency.