RESUMO
The effect of different calcium levels and two limestone granulometries on performance, egg quality, biometry of digestive organs and bone characteristics of light laying hens were evaluated. A total of 270 laying hens were used during 112 days, distributed in a completely randomized design in a 3 x 2 factorial scheme, with 3 levels of calcium (3.8, 4.0 and 4.2%) and 2 limestone granulometries (0.222 and 1.922 mm), totaling 6 treatments with 5 repetitions each. The parameters evaluated were: feed intake, egg production, egg weight and mass, feed conversion per mass and per dozen eggs, albumen, yolk and shell percentage, specific gravity of eggs and shell thickness. In addition, the relative weight of the heart, proventricle, gizzard, liver, pancreas, intestine weight and length, and bone characteristics were also evaluated. A significant interaction was observed for tibia mineral matter. Egg production was influenced by the limestone granulometry, presenting greater value in the treatments which contained fine granulometry limestone. Higher calcium levels of 4.0 and 4.2% provide greater specific density of eggs. Biometric variables and bone characteristics were not influenced by the treatments. In conclusion, it is recommended to use fine-grained limestone (0.222 mm) and a 4% calcium level in diets for light commercial hens, as they improve performance and quality of eggs, without interfering in biometrics of digestive organs and bone characteristics.(AU)
Assuntos
Animais , Osso e Ossos , Cálcio , Ingestão de Alimentos , Galinhas/metabolismo , BiometriaRESUMO
The resistance of gastrointestinal nematodes (GINs) of small ruminants to anthelmintics has required the investigation of new alternatives. The aim of the present study was to evaluate the in vivo anthelmintic activity of an aqueous extract from sisal waste (Agave sisalana) (AESW) against GINs in goats and to observe the animals for toxic effects. Thirty animals that were naturally infected with GINs were distributed into three groups: group I, was treated with daily doses of AESW (1.7 g/kg) for eight days; Group II, the positive control, was treated with a single dose of levamisole phosphate (6.3mg/kg); and group III, the negative control, was left untreated. Faecal eggs counts (FECs), coprocultures and post-mortem worm counts were performed to assess the efficacy of the treatments. Clinical and laboratory analyses were performed to evaluate any toxic effects associated with the treatment. In the goats in groups I and II, a significant reduction (p<0.05) of the number of eggs and infective larvae (L(3)) was observed. The maximum reductions of the FECs were 50.3% and 93.6% for groups I and II, respectively, whereas the percent reductions of the total number of L(3) larvae were 80% (group I) and 85.6% (group II). There was no difference between groups I and III with respect to worm burden, and the percent reductions were 28.8% and 63.4% for Oesophagostomum columbianum and Trichostrongylus colubriformis, respectively. No reduction was detected for the Haemonchus contortus. The positive control group demonstrated a 74% reduction of the parasites that were recovered from the digestive tract. There were no changes in clinical and haematological parameters. The levels of serum urea and creatinine were higher in group I, but remained within the normal range. At necropsy, pale mucous membranes, abomasitis and enteritis were associated with parasitism. In addition, a histological analysis of the liver and kidney did not reveal any changes suggestive of toxicity. A chemical analysis of the AESW demonstrated the presence of saponins, which after acid-hydrolyses reaction, gave the sapogenins hecogenin and tigogenin. The AESW had a low efficacy for the parasitic stages and was moderately effective against eggs and free-living stages. Furthermore, the treatment was not toxic to the goats.