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The eect of breed-production system on the myosin heavy chain 1 (MHC-I), the biochemical characteristics and the colour variables of longissimus thoracis (LT) from seven beef breeds was studied: Asturiana de la MontanÄ a (AM), Asturiana de los Valles (AV), AvilenÄ a-Negra Ibe rica (A-NI), Bruna dels Pirineus (BP), Morucha (MO), Pirenaica (PI) and Retinta (RE) (Age at slaughter between 368 and 541 days; carcass weight between 249 and 334 kg). Signi®cant dierences between breed-production systems were found for all traits evaluated. LT from the MO, a rustic type breed, was the most oxidative (MHC-I, 39.3%; isocitrate dehydrogenase activity, 52 nmol min À1 mg À1 ; pigment content, 188.4 mg acid haematin g À1) and showed a low L* value (32.6) and high a* and C* values (24 and 27.2, respectively). In terms of meat colour (L* and a*) the canonical discriminant analysis separated the breeds into two groups, the AV, the PI and the A-NI (the lightest ones) from the AM and the MO breeds (the reddest and darkest) whereas the BP showed an intermediate position. The RE and the A-NI were distinguished from the others by their high intramuscular fat content. Meat colour was aected by the muscle biochemical traits in the breed-production systems studied. #

Penueus schmitti broodstock was grown from postlarvae in a three‐stage semi‐intensive pond system. Mean weight after 10.5 mo was 51.2 g for females and 33.8 g for mnles. Reproductive response was evaluated in two studies. The first study was conducted with unilaterally ablated or unablated females and males with ejaculated or non‐ejaculated spermntophores. The best response was achieved with ablated females and with non‐ejaculated males (0.87 spawas/maturation tank per d and 22.254 nauplii/maturation tank per d). The second study compared the reproductive response of captive ablated females mated with pond‐reared males or wild males. More nauplii were produced from wild males (78,583 nauplii/maturation tank per d) than from pond‐reared males (57,777 nnuplii/tank per d). The reproductive culture cycle of P. schmitti has been closed for the first time in Cuba on a commercial scale with the collection and stocking of postlarvae of the F1 generation.

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