Sanna Steenfeldt

Enzyme supplementation of wheat-based diets for broilers: 2. Effect on apparent metabolisable energy content and nutrient digestibility

Abstract Two experiments were conducted to determine the effect of enzyme supplementation on the nitrogen-corrected apparent metabolisable energy (AMEn) and apparent nutrient digestibilities in ileum and excreta from male broiler chickens fed diets containing high amounts of wheat (>80%). Four different enzyme preparations were added to the wheat-based diets in varying levels and combinations. The difference between Experiments 1 and 2 consisted in the addition of different enzymes and enzyme levels. Excreta and ileal content were collected from broiler chickens at 3 and 6 weeks of age. At 3 weeks of age enzyme supplementation increased (P

Effect of feeding silages or carrots as supplements to laying hens on production performance, nutrient digestibility, gut structure, gut microflora and feather pecking behaviour

1. An experiment was carried out to examine the suitability of using maize silage, barley–pea silage and carrots as foraging materials for egg-laying hens. Production performance, nutrient digestibility, gastrointestinal characteristics, including the composition of the intestinal microflora as well as feather pecking behaviour were the outcome variables. 2. The protein content of the foraging material (g/kg DM) was on average 69 g in carrots, 94 g in maize silage and 125 g in barley–pea silage. The starch content was highest in the maize silage (312 g/kg DM), and the content of non-starch polysaccharides (NSP) varied from 196 to 390 g/kg, being lowest in carrots. Sugars were just traceable in the silages, whereas carrots contained on average 496 g/kg DM. 3. Egg production was highest in hens fed either carrots or maize silage, whereas hens fed barley–pea silage produced less (219 vs. 208). Although the consumption of foraging material was high (33, 35 and 48% of the total feed intake on ‘as fed’ basis for maize silage, barley–pea silage and carrots, respectively) only a minor effect on nitrogen corrected apparent metabolisable energy (AMEn) and apparent digestibility was seen. At 53 weeks of age, hens fed maize silage had AMEn and apparent digestibility values close to the control group (12·61 and 12·82, respectively), whereas access to barley–pea silage and carrots resulted in slightly lower values (12·36 and 12·42, respectively). Mortality was reduced dramatically in the three groups given supplements (0·5 to 2·5%) compared to the control group (15·2%). 4. Hens receiving silage had greater relative gizzard weights than the control or carrot-fed groups. At 53 weeks of age, the gizzard-content pH of hens receiving silage was about 0·7 to 0·9 units lower than that of the control or carrot-fed hens. Hens fed both types of silage had higher concentrations of lactic acid (15·6 vs. 3·2 µmoles/g) and acetic acid (3·6 vs. 6·1 µmoles/g) in the gizzard contents than the other two groups. The dietary supplements had a minor effect on the composition of the intestinal microflora of the hens. 5. Access to all three types of supplements decreased damaging pecking in general (to feathers as well as skin/cloaca), reduced severe feather pecking behaviour and improved the quality of the plumage at 54 weeks of age. 6. In conclusion, access to different types of foraging material such as silages and carrots improved animal welfare.

Deposition of carotenoids in egg yolk by short-term supplement of coloured carrot (Daucus carota) varieties as forage material for egg-laying hens

BACKGROUND Supplying egg-laying hens with different forage materials may influence egg production and quality. The aim of this study was to examine the short-term effects of standard feed plus 70 g day(-1) per hen of three coloured carrot varieties (orange, yellow and purple) as forage material in comparison with a standard feed control on egg production, egg yolk colour and deposition of carotenoids in the yolk. RESULTS Carrot supplementation reduced feed intakes significantly, but not on a dry matter basis. Orange carrot treatment significantly reduced egg mass production, whereas yellow and purple carrot treatments did not differ from the control. Egg and yolk weights of all carrot-supplemented treatments were significantly lower than those of the control, but yolk percentages were similar. Yolk redness increased significantly in the order control < yellow < orange < purple. A similar trend was seen for yolk yellowness, but yellow and orange carrots reached the same level. Yolk colour and carotenoid contents correlated positively and significantly. In particular, purple carrot treatment increased the yolk content of lutein (>1.5-fold) and beta-carotene (>100-fold) compared with the control. CONCLUSION Supplementing the feed of egg-laying hens with coloured carrots efficiently increased yolk colour parameters and carotenoid contents, which gives opportunities for improved nutritional value of eggs from forage material-supplemented hens.

Fermented feed for laying hens: effects on egg production, egg quality, plumage condition and composition and activity of the intestinal microflora.

1. An experiment with a total of 480 hens (Babcock) was carried out from 16 to 38 weeks of age to evaluate the suitability of wet fermented feed (feed water ratio, 1:1·2–1:1·4) for layers, taking aspects of nutrition and gastrointestinal health into consideration. The production performance, egg shell quality, plumage condition, litter dry matter (DM) content, as well as the composition and activity of the intestinal microbial flora were analysed. 2. Fermented feed was characterised by a high concentration of lactic acid (160–250 mmol/kg feed) and a moderate level of acetic acid (20–30 mmol/kg feed), high numbers of lactic acid bacteria (log 9–10 CFU/g feed) and a pH of approximately 4·5. Feed fermentation reduced the concentration of dietary sugar from 32·1 to 7·3 g/kg DM and the phytate bound phosphorus from 2·7 to 1·9 g/kg DM. 3. Fermented feed seemed to loose attractiveness for the birds quite rapidly, resulting in a more aggressive behaviour and a poorer plumage condition than in birds given dry feed. The use of fermented feed reduced the litter DM content. 4. During the experimental period, the body weight gain of hens receiving fermented feed was 80 g higher than of hens fed the dry mash. Presumably because of an extended adaptation time to the feed, the onset of lay occurred later when hens were fed on fermented feed, resulting in non-significantly reduced total egg production (75 vs. 82%). 5. There was no significant difference between groups with respect to the total egg mass production (g/d/hen, 42 and 45 for fermented feed and dry mash, respectively). Throughout the experimental period, the feed DM intake of hens fed with fermented feed was lower than that of hens receiving the dry mash (110 vs. 125 g). From week 26 to 37, fermented feed improved the feed conversion as compared with the dry mash (g feed DM/g egg mass, 2·28 vs. 2·53). 6. The use of fermented feed increased egg weight in the period from 34 to 37 weeks (61·4 vs. 60·0) and increased shell weight (g/100 g egg weight, 10·2 vs. 9·9) and shell stiffness (N/mm, 161 vs. 150) of eggs collected at 37 weeks. 7. The feeding of fermented feed increased intestinal health by acidification of the upper digestive tract, forming a natural barrier towards infection with acid sensitive pathogens, e.g. E. coli, Salmonella and Campylobacter. 8. It was concluded that fermented wet feed offers potential benefits for health and nutrition, but may become suitable for layers only after the practical problems related to this feeding form have been overcome. However, an early adaptation of the birds during the rearing period seems to be necessary.

The nutritive value of decorticated mill fractions of wheat. 2. Evaluation with raw and enzyme treated fractions using adult cockerels

The nutritive value of raw and enzyme treated whole grain wheat and six mill fractions produced by successive decortication was studied. The mill fractions, which varied considerably in chemical composition, consisted of one fraction enriched in pericarp/testa, one fraction enriched in aleurone and four fractions with graded levels of endosperm tissues. The whole wheat kernels and the six mill fractions constituted 895 g kg−1 of dry matter (DM) of the experimental diets, with fish meal as the only other main component added. The highest content of protein and gross energy (GE) was found in the fraction enriched in aleurone cells. However, a higher amount of non-starch polysaccharides (NSP) was also found in the pericarp/testa (385 g kg−1 DM) and aleurone (182 g kg−1 DM) enriched diets versus the endosperm enriched diets (less than 100 g kg−1 DM). Significantly negative correlations were found between apparent protein digestibility (APD) and insoluble non-starch polysaccharides (I-NSP) (P < 0.05) and the apparent metabolisable energy (AMEn) and I-NSP (P < 0.001). In contrast, soluble NSP (S-NSP) did not significantly contribute to any negative effect on neither digestibility nor AMEn. The APD and AMEn values in the aleurone enriched diet were 84.7% and 12.8 MJ kg−1 DM, and in the pericarp/testa enriched diet 75.2% and 8.0 MJ kg−1 DM, respectively. The APD and AMEn values in the endosperm rich diets were on average 88.6% and 15.6 MJ kg−1 DM, respectively. Results from this study also revealed that the cockerels were able to digest from 10.7% total NSP in pericarp/testa to an average of 42.8% in the endosperm based diets. The lower digestibility and AMEn in pericarp/testa and aleurone enriched diets were caused by the thick cell walls in these layers made up of especially insoluble cellulose and arabinoxylans, which impose a reduction in the availability of nutrients. Enzyme treatment with cell wall degrading and proteolytic enzymes resulted in significant depolymerization and solubilisation of cell wall NSP and of starch. The AMEn increased significantly in the diets based on the whole wheat kernel and pericarp/testa (P < 0.05). The enzyme treatment improved APD significantly in diets with whole wheat kernel and aleurone (P < 0.05). It is assumed that disruption of cell walls owing to enzyme action and release of cell wall content was primarily responsible for the observed improvement in digestibility and AMEn. It is further believed that released cell wall monosaccharides probably have, to some extent, contributed energy to the cockerels.

The nutritive value of decorticated mill fractions of wheat. 1. Chemical composition of raw and enzyme treated fractions and balance experiments with rats

Abstract The chemical composition and nutritive value of raw and enzyme treated whole grain wheat and six mill fractions were studied. The six mill fractions were produced by decortication and consist of one fraction enriched in pericarp/testa, one fraction enriched in aleurone and four fractions with graded levels of endosperm tissues. It was possible, by the advanced milling procedure, to produce mill fractions varying strongly in chemical composition and nutritive value. In the fractions enriched in aleurone cells the concentration of minerals was thus increased two to three times while fat and lysine levels and utilizable protein were 30–40% higher. The digestibility of energy and true protein digestibility were negatively correlated to the dietary fibre level with the lowest values found in the fraction enriched in pericarp/testa (24.0%) and the highest value in the endosperm rich fraction (74.1%). The lowest digestibility of cell wall non-starch polysaccharides was found in the pericarp/testa enriched fraction where the digestibility of arabinoxylans and cellulose was almost the same while the digestibility of arabinoxylans was significantly higher than that of cellulose in the walls of aleurone and endosperm. The strong negative correlation between the digestibility of xylose residue and the arabinose:xylose ratio indicates that the digestibility of arabinoxylans varies in response to the degree of branching. Biological value was higher in the fractions enriched in pericarp/testa, aleurone and germ tissues (≈ 62%) than the whole kernel (56.6%). The highest protein utilization was found in the fraction enriched in aleurone tissues (11.3–11.7%). Enzyme treatment with cell wall degrading and proteolytic enzymes resulted in a significant depolymerization and solubilization of cell wall non-starch polysaccharides and of starch. The digestibility of energy was increased on average by 0.7% (absolute units) by enzyme treatment. The effect of enzyme treatment on true digestibility and biological value was in most cases limited and it was only for the pericarp/testa rich fraction that true digestibility and biological value were significantly improved after enzyme treatment.

Proportion of insoluble fibre in the diet affects behaviour and hunger in broiler breeders growing at similar rates

With a view to alleviate the feeling of hunger in broiler breeders, different types of fibre sources were used in high-fibre diets to increase feed quantity while limiting growth to industry recommended levels. Using scatter feeding, three diets (C1: commercial control diet, 1 × fibre content, 80% insoluble fibre (ISF); H2: 2 × fibre content, 89% ISF; and L2: 2 × fibre content, 71% ISF) were each fed to 10 groups of 16 broiler breeder chickens. Similar growth rates were obtained on different quantities of food with all birds reaching commercial target weight at 15 weeks of age. In a hunger test, birds fed C1 ate significantly faster and showed a higher compensatory feed intake than birds on diets H2 and L2, indicating that the two high-fibre diets did reduce the level of hunger experienced by the birds. Behavioural observations carried out at 14 weeks of age showed high levels of tail pecking in birds fed C1 and almost none in birds fed L2, whereas birds fed H2 were intermediate. Stereotypic pecking at fixtures was seen twice as frequently in birds fed C1. Birds on diet L2 displayed behavioural signs indicative of discomfort, and the high water usage on this diet created problems with litter quality. Birds on diet H2 continued to show foraging behaviour throughout the day, and were more frequently engaged in dust bathing and other comfort behaviour. This experiment indicates that high-fibre diets can alleviate the feeling of hunger currently experienced by broiler breeders, and a high ratio of ISF may improve the well-being of the birds.

Splitting the scotoperiod: effects on feeding behaviour, intestinal fill and digestive transit time in broiler chickens

1. The aim of this study was to evaluate how splitting the dark period (scotoperiod) affects feeding behaviour and associated intestinal measures in broilers. 2. Ross 308 broilers were reared to 37 d in groups given either a daily 8-h continuous scotoperiod (DARK 8) or an intermittent light schedule with two equally spaced 4-h scotoperiods (DARK 4 + 4), which yielded the same total duration of darkness per 24 h. 3. Feeding behaviour was recorded weekly from 24-h video recordings of 24 groups each of 64 birds. Empty intestinal weights as well as their contents were measured weekly at 4 time points (n = 192). Digestive transit time was estimated on d 29 using a chromic oxide marker; production variables and the extent of foot pad dermatitis were also recorded. 4. In the 3 h prior to a scotoperiod, feeding activity increased in chickens from DARK 8 but not DARK 4 + 4. This increase was reflected in a higher relative content of the crop in DARK 8 at this time. 5. Immediately following the scotoperiod, feeding activity peaked and, although the chickens in DARK 4 + 4 expressed more feeding behaviour in the first 20 min after the scotoperiod, the chickens in DARK 8 had overall higher feeding activity across the day. However, DARK 4 + 4 had a higher feed intake and weight gain. The occurrence and severity of foot pad dermatitis was similar between treatments. 6. In conclusion, broilers modify their feeding behaviour according to the prevailing light schedule. Eight consecutive hours of darkness reduced growth, but did not affect overall feed conversion efficiency, and did not appear to exacerbate hunger or foot pad dermatitis to any great extent.

Sustainable development perspectives of poultry production

The concept of ‘sustainability’ or ‘sustainable development’ is multi-dimensional, encompassing economic, environmental, social, and institutional governance aspects. The theoretical framework for this article on sustainability in poultry production is built on this multi-dimensional understanding of the concept, acknowledging that it is complex and contested. It is challenging to analyse or discuss the sustainability of one single sector within agriculture, because this sector is part of a global food system, and a systems approach is necessary. This article gives examples of elements which link to one or more of the four aspects, e.g., pollution and antibiotic use, biodiversity (environmental aspects), conditions for farm workers and animal welfare (social aspects), governance of the food chain (institutional aspects), and the development of poultry from a valuable food to a cheap staple food throughout major parts of the world (economic aspects). There are numerous potential pathways for sustainable development of poultry production. Poultry are living, sentient animals that can be well integrated into many different types of urban and rural farming systems, where they benefit from and contribute to such systems and to the livelihood of households around the globe, with special emphasis on women. Furthermore, local production provides potential for production with minimum transport and, concomitantly, minimum usage of fossil fuels. Among the terrestrial animals, poultry has the best conversion rate of feed to human food and the smallest environmental footprint in terms of energy and water use per kg meat or eggs produced.

The effects of kale (Brassica oleracea ssp. acephala), basil (Ocimum basilicum) and thyme (Thymus vulgaris) as forage material in organic egg production on egg quality.

1. In organic egg production, forage material as part of the diet for laying hens is mandatory. The purpose of the present study was to examine the effect of feeding with forage materials including maize silage, herbs or kale on egg production and various egg quality parameters of the shell, yolk colour, egg albumen, sensory properties, fatty acid and carotenoid composition of the egg yolk. 2. A total of 5 dietary treatments were tested for 5 weeks, consisting of a basal organic feed plus 120 g/hen.d of the following forage materials: 1) maize silage (control), 2) maize silage incl. 15 g/kg basil, 3) maize silage incl. 30 g/kg basil, 4) maize silage incl. 15 g/kg thyme, or 5) fresh kale leaves. Each was supplied to three replicates of 20 hens. A total of 300 hens was used. 3. Feed intake, forage intake and laying rate did not differ with treatment, but egg weight and egg mass produced increased significantly with the kale treatment. 4. The egg shell strength tended to be higher with the kale treatment, and egg yolk colour was significantly more red with the kale treatment and more yellow with basil and kale treatments. The albumen DM content and albumen gel strength were lowest with the thyme treatment. By sensory evaluation, the kale treatment resulted in eggs with less sulphur aroma, higher yolk colour score, and more sweet and less watery albumen taste. Furthermore, the eggs of the kale treatment had significantly higher lutein and β-carotene content. Also, violaxanthin, an orange xanthophyll, tended to be higher in kale and eggs from hens receiving kale. 5. In conclusion, forage material, especially basil and kale, resulted in increased egg production and eggs of high and differentiable quality.