A by-product of swine slaughtering as a protein source in broiler diets: effects on performance, composition of excreta, litter quality and on foot pad health.

Foot pad dermatitis (FPD) is of great concern in poultry industry, and dietary strategies are needed to improve foot pad health because of animal welfare and economic reasons. As the main factor for the development of FPD is the DM content of litter (consisting mainly of excreta; Kamphues et al., 2011), there are different dietary approaches to influence this disease pattern. In two consecutive trials, a total of 200 broilers were kept from day 7 until the 35th day of life. They were divided into four groups at each trial and fed with one of four experimental diets, based on wheat and corn mainly, but differing in the protein source: Group 1 was fed a diet with soya bean meal (SBM) as the main protein source, whereas Group 2, Group 3 and Group 4 were assigned to diets with 4, 8 and 12% of a protein-rich (66.7% CP in DM) by-product of swine slaughtering [Swine Protein Meal (SPM); in exchange for SBM]. The inclusion of 12% SPM resulted in a decreased dietary potassium content of about 3 g/kg diet (Group 1 vs. 4). Increasing dietary levels of the by-product (8 and 12%) led to lowered feed intake (Group 1 vs. 4: ~10%) and weight gain (Group 1 vs. Group 4: ~8.5%). Although highest DM contents of excreta and litter were determined in Group 4, foot pad health was not influenced positively as hypothesized. Remarkable was the observed 'stickiness' of excreta when the by-product was included in the diet at increasing levels, presumably due to the high proportion of bones in the by-product. In conclusion, substituting SBM by 4% of the by-product of swine slaughtering in broiler diets did not impair performance parameters, but led to the most favourable foot pad scores in this study.

Effects of a carbohydrase complex added in different inclusion rates in feeds for broilers on growth performance, digesta viscosity and foot pad health.

Foot pad dermatitis (FPD) is a widespread disease in poultry and important for economic and animal welfare reasons. It is well recognized that using non-starch polysaccharide (NSP)-degrading enzymes can affect excreta/litter quality (not only in terms of moisture content but also regarding water evaporation) at high stocking densities and might help to prevent FPD and further negative effects of NSP. This study aimed to evaluate effects of a carbohydrase complex (CC) in different dietary inclusion rates on performance, digesta viscosity and foot pad health in broilers from 9 to 37 days of life. In total, 240 broilers were divided into 12 floor pens of 20 birds and received one of four different experimental diets. The four wheat- and soyabean meal-based diets only differed in the inclusion rate of CC: 0%, 50%, 100% and 500% of the recommended dose of CC (Endo-1,4-ß-xylanase and Endo-1,3(4)-ß-glucanase; 50 g/t). The addition of CC led to a significant decrease of digesta viscosity in the proximal small intestine, a tendency of improved feed conversion ratio, and significantly favoured FPD-scores (Treatment 2). At the higher tested inclusion rate of CC (500% of recommended dose), the FPD score was worser than in the treatments with 50% and 100% of the recommended enzyme dosage. No improvements among treatments were observed in terms of body weight and dry matter content of excreta and litter at the end of trial. The low positive effects on foot pad health in this study were presumably associated with the low NSP content in the experimental diets (soluble arabinoxylans: 7.38 g/kg as fed). In conclusion, the addition of the evaluated CC reduced digesta viscosity. An improvement of foot pad health could only be seen in the treatment with 50% of the recommended enzyme dosage in the diet.

The postnatal development of myelinated nerve fibres in the visual cortex of the cat: a stereological and electron microscopical investigation.

With the aid of stereological procedures the development of myelinated nerve fibres (MF) was quantitatively investigated in electron micrographs of the visual cortex from animals of different ages: 36 days-old, the age at which fibres first appear, through adulthood. A short description of tissue treatment, methods and qualitative results is given. The following quantitative results are presented: 1. Myelinization begins at about the 36th day postpartum and is not completed by the 164th day. At this time a lack of about 20% MF can be observed. 2. The average diameter of MF decreases from 1.3 mum to 0.8 mum from day 36 to adulthood. 3. The first MF appear near the border of the album. 4. Beginning with the 55th day, small MF arise in layer I, showing two periods of growth. 5. The maximum MF density in the region of layer IV corresponds to the strip of Baillarger. Other aspects of visual cortex development are dealt with in the Discussion. The following conclusions can be drawn: a) The growing of in- and output-MF is completed first. b) The development of the internal connecting systems in layers I and IV begins a little later and is completed by the 5th month. c) The MF in layers II and III appear after the 4th month. Kaes (1907) has also described a continuation of MF growth in man lasting into the twenties.