A rifampin-resistant Lactobacillus salivarius strain, CTC2197, was assessed as a probiotic in poultry, by studying its ability to prevent Salmonella enteritidis C-114 colonization in chickens. When the probiotic strain was dosed by oral gavage together with S. enteritidis C-114 directly into the proventriculus in 1-day-old Leghorn chickens, the pathogen was completely removed from the birds after 21 days. The same results were obtained when the probiotic strain was also administered through the feed and the drinking water apart from direct inoculation into the proventriculus. The inclusion of L. salivarius CTC2197 in the first day chicken feed revealed that a concentration of 105 CFU g−1 was enough to ensure the colonization of the gastrointestinal tract of the birds after 1 week. However, between 21 and 28 days, L. salivarius CTC2197 was undetectable in the gastrointestinal tract of some birds, showing that more than one dose would be necessary to ensure its presence till the end of the rearing time. Freeze-drying and freezing with glycerol or skim milk as cryoprotective agents, appeared to be suitable methods to preserve the probiotic strain. The inclusion of the L. salivarius CTC2197 in a commercial feed mixture seemed to be a good way to supply it on the farm, although the strain showed sensitivity to the temperatures used during the feed mixture storage and in the chicken incubator rooms. Moreover, survival had been improved after several reinoculations in chicken feed mixture.

A profit function was designed for an industrial commercial rabbitry with the most common management in industrial rabbit production. The incomes, costs, and profit function were calculated and economic weights of the traits were estimated. The variable costs (feeding, artificial insemination, health and replacement) represented 62% of the total costs, and the fixed costs (labour, utilities, amortisation and administration) represented 38% of the total costs. Major costs were feeding of fattening kits and labour cost, at 26% and 18% of the total cost, respectively. The economic weights were feed conversion rate during fattening (-20.2 €/[g feed/g liveweight]), number of kits born alive (15.7 €/kit), pregnancy rate (1.7 €/percentage unit), weaning survival (1.7 €/percentage unit), fattening survival (2.0 €/percentage unit), daily feed intake (-0.50 €/(g feed/d)), daily gain during fattening (1.33 €/(g weight/d)), and replacement rate (-0.29 €/percentage unit). When varying the prices of kg of fattening feed and kg of liveweight, only the economic weights of feed conversion rate during fattening in the first case and the number of kits born alive in the second case changed considerably. Changes in labour cost produced appreciable changes in the whole production cost. Although economic weights are robust to changes in prices, these weights should be recalculated after some generations of selection, because changes in the mean of the traits due to selection can also change economic weights.

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The effect of selection for growth rate on relative growth of the rabbit body components was studied. Animals from the 18th generation of a line selected for growth rate were compared with a contemporary control group formed with offspring of embryos that were frozen at the seventh generation of selection of the same line. A total of 313 animals were slaughtered at 4, 9, 13, 20, and 40 wk old. The offal, organs, tissues, and retail cuts were weighed, and several carcass linear measurements were recorded. Huxley's allometric equations relating the weights of the components with respect to BW were fitted. Butterfield's quadratic equations relating the degree of maturity of the components and the degree of maturity of BW were also fitted. In most of the components studied, both models lead to similar patterns of growth. Blood was isometric or early maturing and skin was late maturing or isometric depending on the use of Huxley's or Butterfield's model. Full gastrointestinal tract, liver, kidneys, thoracic viscera, and head were early maturing, and the chilled carcass and reference carcass were late maturing. The retail cuts of the reference carcass showed isometry (forelegs) or late maturing growth (breast and ribs, loin, hind legs, and abdominal walls). Dissectible fat of the carcass and meat of the hind leg had a late development, whereas bone of the hind leg was early maturing. Lumbar circumference length was later maturing than the carcass length and thigh length. Sex did not affect the relative growth of most of the components. Butterfield's model showed that males had an earlier development of full gastrointestinal tract and later growth of kidneys than females. No effect of selection on the relative growth of any of the components studied was found, leading to similar patterns of growth and similar carcass composition at a given degree of maturity after 11 generations of selection for growth rate.

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