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The hypothesis that dietary inclusion of microbial phytase improves apparent calcium (Ca) digestibility thereby allowing a lower dietary Ca inclusion without compromising growth performance was tested. One-day-old male Ross 308 broilers (25 birds/pen, 9 pens/treatment) were assigned to 8 experimental diets containing one of 4 dietary Ca to retainable P (rP) ratios (1.3, 1.8, 2.3, and 2.8) with (1,000 FTU/kg) or without microbial phytase. On d 21 to 23, digesta from different intestinal segments of 8 birds per pen were collected to determine apparent Ca and P digestibility. Mid duodenal mucosa was collected for expression of Ca (CaBP-D28k, PMCA1) and P (NaPi-IIb, PiT-1, PiT-2, and XPR1) transporters by RT-qPCR. Dietary phytase inclusion in low Ca/rP diets increased Ca digestibility in the distal ileum (Pinteraction = 0.023) but not the proximal or distal jejunum. Broilers receiving the lowest Ca/rP displayed the lowest body weight gain, highest feed conversion ratio (P < 0.001), and lowest tibia strength, irrespective of dietary phytase inclusion. Incremental dietary Ca/rP linearly reduced P digestibility to a greater extent in the absence of phytase in the distal jejunum and ileum (Pinteraction = 0.021 and 0.001, respectively). Incremental dietary Ca/rP linearly reduced serum P more in phytase-free diets (Pinteraction < 0.001), and lowered duodenal expression of P transporters NaPi-IIb, PiT-2, and XPR1 (P = 0.052, 0.071 and 0.028, respectively). Incremental dietary Ca/rP linearly increased (P < 0.001) serum Ca irrespective of phytase inclusion, accompanied by a lower (P < 0.001) duodenal expression of Ca transporters CaSR, CaBP-D28k and PMCA1 and Ca-pore forming claudins CLDN-2 and CLDN-12. Dietary phytase increased (P = 0.026) NaPi-IIb but reduced (P = 0.029) CLDN-2 expression. Incremental Ca/rP reduced Ca and P digestibility, increased serum Ca, lowered serum P and inhibited mRNA levels of Ca and P-related transporters, indicating that these transporters and CLDN contribute to the observed effect of dietary Ca and phytase on Ca and P absorption. Despite the improvement in Ca digestibility, dietary phytase did not restore the compromised growth performance and tibia strength of broilers fed a Ca-deficient diet, leading to rejection of the hypothesis.

This study was designed to evaluate the effects of green light emitting diode (LED) light during incubation and dietary organic macro and trace minerals during rearing on tibia morphological, biophysical, and mechanical characteristics of broiler chickens at slaughter age. The experiment was setup as a 2 × 2 × 2 factorial arrangement, with the following treatments: 1) light during incubation (green LED light or darkness), 2) macro mineral source during rearing (organic or inorganic Ca and P), and 3) trace mineral source during rearing (organic or inorganic Fe, Cu, Mn, Zn, and Se). A total of 2,400 eggs (Ross 308) were either incubated under green LED light (16L:8D) or in complete darkness. After hatch, a total of 864 male broiler chickens were reared until slaughter age (day 42) and provided with 1 of 4 diets, differing in macro and/or trace mineral source. During rearing, the experiment had a complete randomized block design with 9 replicate pens per treatment and 12 chickens per pen. At slaughter age (day 42), 2 chickens per replicate were randomly selected and tibia bones were obtained. Tibia weight, length, thickness, osseous volume, pore volume, total volume, mineral content, mineral density, ultimate strength, and stiffness were determined. Green LED light during incubation did not affect any of the tibia characteristics. Dietary organic macro minerals positively affected most of the tibia morphological, biophysical, and mechanical characteristics compared to the inorganic macro minerals, whereas trace mineral sources did not affect tibia characteristics. It can be concluded that dietary organic macro minerals Ca and P stimulated tibia characteristics, whereas green LED light during incubation and dietary trace minerals during rearing did not affect tibia characteristics, locomotion, or leg disorders.

The hypothesis was tested that an increased digestion of coarse compared with fine limestone can alleviate the negative effects of a low dietary Ca/P ratio on the growth performance and characteristics of tibia strength (CTS) in broilers. A total of 1,152 Ross 308 broiler chickens received a standard commercial starter feed from day 0 to 13. From day 14 onward, birds received 1 of 12 diets containing 1 of 6 Ca/P ratios (0.50, 0.75, 1.00, 1.25, 1.50, and 1.75) and 1 of 2 limestone particle sizes (

The increasing demand for animal protein by the growing world population intensifies the exploration of novel feed sources. This study evaluated the nutritional value of six intact seaweed species (i.e. the brown species Saccharina latissima, Laminaria digitata, and Ascophyllum nodossum, the red species Palmaria palmata, and Chondrus crispus and green species Ulva lactuca), collected from the coast of Ireland, Scotland and France as an ingredient for animal feed. The nutrient composition, in vitro digestibility, and in vitro gas production simulating rumen fermentation, were determined. The nutrient contents (g/kg dry matter), both between and within species, were highly variable, ranging from 45–248 for crude protein, 351–691 for non-starch polysaccharides, and 173–445 for ash. Overall, the brown seaweeds had the highest non-starch polysaccharides content, whereas samples of the red and green seaweeds had an amino acid content up to 265 g/kg dry matter. All samples had a substantial non-protein nitrogen fraction, varying from 0.12–0.29 of nitrogen. The fibre fractions of brown seaweeds showed different properties than land-based plants, as illustrated by a lower analysed neutral detergent fibre than acid detergent fibre content. The ileal organic matter and nitrogen digestibility, as well as the total tract organic matter digestibility (mean digestibility coefficients: 0.81, 0.89 and 0.88, respectively) were lower for all seaweeds compared to soybean meal (digestibility coefficients: 0.84, 0.98 and 0.97, respectively). S. latissima, L digitata, P. palmata and U. lactuca had a higher maximum gas production than alfalfa, but lower than sugar beet pulp. Based on the protein content and amino acid-pattern, intact P. palmata and U. lactuca would be a valuable protein source for farm animals, with the high non-starch polysaccharides and non-protein nitrogen contents and a low in vitro digestibility potentially limiting their use as a feed ingredient for monogastric species. The fermentability of L. digitata, S. latissima and P. palmata indicate that these intact seaweeds may have a higher nutritional value in ruminants. The high ash content in all seaweed species hampers the use of intact seaweed for both ruminants and monogastrics. Extraction of protein and other favourable components, while reducing the ash content, seems an important step towards seaweed inclusion in animal diets. Further identification and characterisation of seaweed polysaccharides is required to understand and improve the digestibility of seaweed fractions.

Feather pecking (FP) by laying hens is a significant welfare issue in the poultry industry. Pecking at and pulling out feathers of conspecifics can seriously reduce the well-being of birds and causes economic losses for the farmer. Records of FP in laying hen flocks from the last 20 years show a prevalence of between 24% and 94%. Several research groups worldwide have hypothesised about the causes of FP. From a nutritional point of view, re-directed behaviour and feather eating seem to be the most plausible causes. The gut microbiome seems to be involved in FP due to its influence on hormonal pathways and as it is influenced by the diet, which might include feathers ingested by the hens. Bird experiences during the rearing period are related to FP in later life by possible effects on the physiological development of the pullets. Most likely, pullets experience a sensitive period within the first few weeks post-hatch during which FP can develop due to various factors such as hormonal influences, nutrition and (the lack of) environmental enrichment. Nutrition could influence FP in two ways. Imbalances in certain nutrients, such as amino acids may have a direct effect on physiological mechanisms that trigger FP. Furthermore, ingredients such as roughages, fibres and non-nutritive ingredients may have an effect on exploratory and foraging or feeding behaviour. Literature (mainly in adult layers) shows that nutritional interventions increased eating time by 23–45% and/or the mean retention time of feed in the gut by 2.9–6.0 min/g fibre, and reduced or delayed FP. Using nutritional strategies (i.e. provision of specific AA profiles and/or high fibrous ingredients) during the sensitive period during rearing could prevent ultimately the development of FP, by altering the pullets’ (gut) physiology and/or her time allocation. Research focussing on critical periods during rearing should be initiated.

The use of seaweed as feed ingredient is gaining interest but the high ash content, low nutrient digestibility, short shelf life and poor economic feasibility hamper practical application. This study investigates the effect of washing, ensiling and extraction processes on the nutritional value of seaweed products for broilers, based on nutrient content and in vitro and in vivo digestibility. The effects of ensiling, washing and extraction processes were evaluated using Saccharina latissima, Laminaria digitata and Ulva lactuca, with 2, 4, and 6 h incubations in an in vitro simulated digestibility model, to obtain insight into the kinetics of digestibility. In an in vivo study, 160 Ross 308 male broilers were fed (day 14–22) a basal grower diet, or the basal grower diet with 100 g/kg of S. latissima silage or silage residue. Performance and ileal and total tract nutrient digestibility were determined. Washing and ensiling reduced the ash content, but also the in vitro organic matter digestibility (both P < 0.001). Washing also reduced nitrogen digestibility (P < 0.001). Extraction of seaweed decreased in vitro organic matter and nitrogen digestibility. Feeding seaweed diets to broilers resulted in a higher feed conversion ratio (1.62 versus 1.86 and 1.77 for broilers fed the basal, silage and silage residue diets respectively, P < 0.001) without increase in final body weight. Feeding S. latissima silage residue compared to silage resulted in a slightly better broiler performance and a higher amino acid digestibility. In conclusion, washing, ensiling and extraction processes reduce the nutritional value of the seaweed products, and do not make seaweed suitable for inclusion in broiler diets. To create suitable seaweed products for inclusion in broiler diets, a further reduction in the ash content and increase in digestibility is needed.

An experiment was conducted to investigate the effects of dietary inclusion of rye, a model ingredient to increase gut viscosity, between 14 and 28 d of age on immune competence-related parameters and performance of broilers. A total of 960 day-old male Ross 308 chicks were weighed and randomly allocated to 24 pens (40 birds per pen), and the birds in every 8 replicate pens were assigned to 1 of 3 experimental diets including graded levels, 0%, 5%, and 10% of rye. Tested immune competence-related parameters were composition of the intestinal microbiota, genes expression in gut tissue, and gut morphology. The inclusion of 5% or 10% rye in the diet (d 14 to 28) resulted in decreased performance and litter quality, but in increased villus height and crypt depth in the small intestine (jejunum) of the broilers. Relative bursa and spleen weights were not affected by dietary inclusion of rye. In the jejunum, no effects on number and size of goblet cells, and only trends on microbiota composition in the digesta were observed. Dietary inclusion of rye affected expression of genes involved in cell cycle processes of the jejunal enterocyte cells, thereby influencing cell growth, cell differentiation and cell survival, which in turn were consistent with the observed differences in the morphology of the gut wall. In addition, providing rye-rich diets to broilers affected the complement and coagulation pathways, which among others are parts of the innate immune system. These pathways are involved in eradicating invasive pathogens. Overall, it can be concluded that inclusion of 5% or 10% rye to the grower diet of broilers had limited effects on performance. Ileal gut morphology, microbiota composition of jejunal digesta, and gene expression profiles of jejunal tissue, however, were affected by dietary rye inclusion level, indicating that rye supplementation to broiler diets might affect immune competence of the birds.

The objective of this ring test was to investigate the prececal phosphorus (P) digestibility of soybean meal (SBM) in broiler chickens using the trial protocol proposed by the World's Poultry Science Association. It was hypothesized that prececal P digestibility of SBM determined in the collaborating stations is similar. Three diets with different inclusion levels of SBM were mixed in a feed mill specialized in experimental diets and transported to 17 collaborating stations. Broiler chicks were raised on commercial starter diets according to station-specific management routine. Then they were fed the experimental diets for a minimum of 5 d before content of the posterior half of the ileum was collected. A minimum of 6 experimental replicates per diet was used in each station. All diets and digesta samples were analyzed in the same laboratory. Diet, station, and their interaction significantly affected (P < 0.05) the prececal digestibility values of P and calcium of the diets. The prececal P digestibility of SBM was determined by linear regression and varied among stations from 19 to 51%, with significant differences among stations. In a subset of 4 stations, the prececal disappearance of myo- inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate)-P; InsP6-P) also was studied. The prececal InsP6-P disappearance correlated well with the prececal P digestibility. We hypothesized that factors influencing InsP6 hydrolysis were main contributors to the variation in prececal P digestibility among stations. These factors were probably related to the feeding and housing conditions (floor pens or cages) of the birds in the pre-experimental phase. Therefore, we suggest that the World's Poultry Science Association protocol for the determination of digestible P be should extended to the standardization of the pre-experimental period. We also suggest that comparisons of P digestibility measurements among studies are made only with great caution until the protocol is more refined. info:eu-repo/semantics/publishedVersion

1. This study determined the effects of three protein sources (PS), each at two digestibility crude protein (DCP) levels, on performance, gut morphology and fermentation characteristics in the hindgut of broilers. 2. It was hypothesised that broilers fed ingredients high in indigestible CP, i.e. rapeseed meal (RSM) or maize gluten (MG), could potentially cause reduced growth, impaired gut health, and more protein fermentation products in caecal digesta. Increasing the DCP level in each of the indigestible CP diets may compensate for these detrimental effects. 3. In total, 288 one-d-old male Ross 308 broilers were used in a completely randomised 3 × 2 factorial design, with six replicate pens per treatment. Three PS: soybean meal (SBM), rapeseed meal (RSM) or maize gluten (MG), and two DCP levels: 15.8 and 17.2% were used. 4. Broilers fed SBM had increased feed intake and BWG and improved FCR compared with those fed RSM and MG diets. Broilers fed high DCP had better performance compared with those on low DCP. No significant effects of PS or DCP level were found on gastrointestinal tract development, caecal ammonia or volatile fatty acid concentrations. 5. Broilers fed SBM had longer villi, smaller crypts and increased villus height to crypt depth ratio compared with those fed RSM and MG diets. Broilers fed RSM diet had a lower caecal pH, and had 16.5% and 14.9% more branched chain fatty acid contents in caecal digesta compared with those fed SBM and MG diets, respectively, indicating more proteolytic fermentation. 6. Replacing SBM by RSM and MG negatively affected growth performance and gut morphology. Hindgut protein fermentation was substantially increased in RSM fed birds. 7. To a certain extent, retarded growth performance in RSM and MG fed birds could be counterbalanced by increasing the dietary level of digestible CP.

Processed Animal Proteins (PAPs) have long been banned from farm animal diets in the EU. In this period, raw material selection and processes to prepare PAPs have been improved and diversified allowing for a range of products available for inclusion in animal diets. As a consequence, the products and their respective specifications in present feedstuff tables do not cover the composition and quality of presently available PAPs. This report presents the methods and results of a study, conducted by Wageningen Livestock Research at the request of European Fat Processors and Renderers Association (EFPRA), in which the total tract digestibility of proximate components and ileal phosphorus, calcium and amino acid digestibility of 2 PAPs of pig origin in broiler chickens were evaluated. The results from this study showed that the chemical composition of the new PAPs are broadly similar to the 'former' PAPs, but that the AME and the digestibility of crude fat, crude protein and amino acids of the new PAPs was lower. Therefore it is recommended, once the ban on the use of animal proteins in broiler diets ends, to update the present PAP table figures for broilers.

The aim of the current study was to determine the degradation of free amino acids in freshly produced liquid feeds. It can be concluded that the level of degradation of free amino acids in liquid feeds might be limited, provided the conditions applied in the current study.---Het doel van deze studie was na te gaan in welke mate vrije aminozuren gevoelig zijn voor afbraak onder brijvoercondities. Onder de toegepaste condities in dit onderzoek trad er slechts in beperkte mate degradatie van vrije aminozuren in de brijvoeders op.

Nutrition is a crucial factor for growth and bone development in broiler chickens. Adjustments in dietary ingredients might affect bone development and consequently locomotion related problems. This study was designed to evaluate effects of dietary organic minerals (ORM), fish oil (FISH), and hydrolyzed collagen (COL) on growth performance and tibia characteristics of broiler chickens. A total of three hundred eighty four 1-day-old Ross 308 male broiler chickens were used in a complete randomized block design with 4 diet groups and 8 replicates per diet group. In the ORM diet, the inorganic macro and trace minerals were replaced by their organic varieties. In the FISH diet, palm oil and soybean oil were partly replaced by FISH. In the COL diet, soybean meal was partly replaced by COL. Results showed that the ORM and COL diet groups reached a higher body weight (BW) at 42 D of age than the FISH diet group, whereas the control group was in between. The feed conversion ratio between day 1 and 42 was lower in the ORM and COL diet groups than in both other diet groups. On day 28, 35, and 42, gait score (GS), Varus Valgus deformity, tibia length (TL), thickness, femoral and metatarsal head thickness (THT), mineral content (TMC), mineral density (TMD), breaking strength (TBS), stiffness (TSF), and energy to fracture (TEF) were measured (n = 3/replicate). The ORM diet group had higher TL at day 42, higher THT at day 28, higher TMC at day 42, higher TMD at day 28, 35, and 42, higher TBS at day 42, higher TSF at day 35 and 42, and higher TEF at day 42 compared to the FISH diet group, with the COL and control diet groups in between. It can be concluded that replacing dietary inorganic macro and trace minerals by their organic varieties seems to stimulate tibia dimensions, strength, and mineral content of broiler chickens. On the contrary, FISH appears to negatively affect tibia characteristics.

A study with 884 Ross 308 male broilers, housed in 68 floor pens (0.75 m2) from 0 to 35 days of age was conducted to evaluate the effects of low crude protein (CP) diets, with partial replacement of soybean meal by free amino acids (AA), on performance, slaughter yields, litter quality and footpad lesions. During the first 11 d, all broilers received the same control starter diet (216 g/kg CP, 11.5 g/kg apparent fecal digestible (AFD) lysine, and 2900 kcal/kg AMEn). Thereafter, four experimental feeding programs with different levels of dietary CP (control and control with 1% (CP-1%), 2% (CP-2%) and 3% (CP-3%) less CP units) were provided in both the grower and finisher phase. In the control grower and finisher diet, the CP content was 208 and 198 g/kg, respectively. All diets were formulated to meet or exceed the recommendations concerning AFD AA, and to be iso-caloric within each feeding phase. Feed and water were provided for ad libitum intake during the entire experimental period. None of the low CP feeding programs affected body weight gain, feed intake or mortality from 0 to 35 d. However, CP conversion was improved with the reduction of CP content of the diet. Broilers fed the CP-2% or CP-3% feeding program had an improved feed conversion ratio. Broilers fed the low CP protein feeding programs had a better litter quality and less footpad lesions, compared to broilers fed the control feeding program. Broilers fed the CP-3% feeding program had a lower breast meat yield than broilers fed the control feeding program. Slaughter yields of broilers fed CP-1% or CP-2% feeding program did not differ from the control feeding program. This study demonstrated that the CP content of grower and finisher diets can be reduced by 2.2–2.3% units without adverse effects on growth performance of broilers, while CP reduction seems promising to reduce nitrogen excretion from broiler houses, improve bird welfare, and reduces dependence on vegetable protein sources.

From December 2017 onward, including non-organic protein sources in diets for organic poultry will no longer be allowed in the EU. Moreover, in the EU the use of synthetic amino acids in organic diets is prohibited. The main dietary challenge in European organic egg production is to fulfill the protein requirement, especially the methionine (Met) requirement of the hens. Currently available Met-rich ingredients are discussed. In the group of ingredients of plant origin, expelled sunflower seed has a relatively high digestible Met content and is also commonly available. Met content of plant ingredients can be increased by selection of high Met varieties and by specifically breeding on high Met content, e.g. by crossing different breeds. Plant processing techniques might be helpful to concentrate the protein and digestible Met content of ingredients. Applying the dry fractionation technique on legumes and cereals might result in protein concentrates with CP content of at least 50%. A further development of simple separation techniques, which separate the hulls from the other plant fractions and reduce the fiber content after de-hulling, might be helpful to increase digestible Met content. Energy dilution of the diet, concomitant with a proportional reduction in other nutrients, is an option as well to fulfill the requirement of 100% organic diets. As a consequence, hens have to consume more feed to meet their nutrient requirements. There are options to fulfill the requirement of 100% ingredients of organic origin, but if the practical, economical, and footprint issues are taken into account, the list of options is very small.

The current study was conducted to evaluate the effect of feed supplementation with a phytogenic product (equal mixture of thymol plus carvacrol; T+C) on performance, nutrient retention, volatile fatty acid (VFA) profiles, cecum microbial ecosystem, serum parameters and characteristics of gastrointestinal tract of broilers fed on wheat-based diets with or without an NSP-degrading enzyme product (xylanase plus β-glucanase; E) from d 0 to 42. Six dietary treatments were arranged according to a factorial design with three levels of T+C (0, 100 and 200. mg/kg of diet) and two levels of E (0 and 0.5 g/kg of diet). Each treatment was replicated five times with 12 chicks per replicate. There was no interaction effect between E and T+C on any of the measured parameters. Compared with the control group, birds fed diets containing E or T+C had a higher ( P

In a study with 910 Ross 308 male broilers, housed in 70 floor pens bedded with wood shavings, the effect of digestible glycine+serine content (5 levels ranging from 12.4 to 15.7 g/kg and 11.4 to 14.9 g/kg in grower and finisher diets, respectively) in low-protein diets was studied from 10 – 35 days of age. In this study, also the glycine-sparing effect of threonine was studied. In total seven different treatments were studied: a control treatment (a normal/high protein diet), five low-protein dietary treatments with increasing levels of digestible glycine+serine and a low-protein dietary treatment in which extra threonine was supplemented to the diet with the lowest glycine+serine level. Growth performance results, slaughter yields, litter quality, litter composition and footpad score were measured. This study showed that the glycine+serine level in low-protein feed did not have a noticeable effect on the production results, slaughter yields, litter quality and foot pad lesion. Based on this study it was concluded that a digestible glycine+serine dose in low-protein diets of 12.4 g/kg and 11.4 g/kg in grower and finisher phase, respectively, is sufficient. In een dosis-respons studie met 910 Ross 308 vleeskuikenhanen, die werden gehuisvest in 70 grondhokken met strooisel, werd het effect van het glycine(+serine) niveau in laag-eiwitvoeders onderzocht in het leeftijdstraject van 10 – 35 dagen. In totaal werden vijf verteerbare glycine+serine niveaus, oplopend in evenredige stappen van 12,4 tot 15,7 g/kg in de groeifase en van 11,4 tot 14,9 g/kg in de eindfase, onderzocht. Daarnaast werd het mogelijk glycine-besparende effect van threonine bestudeerd; hiertoe werd aan het laag-eiwit voer met het laagste glycine+serine niveau extra threonine toegevoegd. De resultaten van de laag-eiwitvoeders werden vergeleken met een voer met een normaal eiwitgehalte met eenzelfde aminozurenprofiel. Uit dit onderzoek kwam naar voren dat het glycine+serine niveau in laag-eiwitvoeders geen noemenswaardig effect had op de productieresultaten, slachtrendementen, strooiselkwaliteit en voetzoollaesiescore en dat een verteerbaar glycine+serine gehalte van 12,4 g/kg en 11,4 g/kg in respectievelijk het groei- en eindvoer voldoende is

This report presents the methods and results of a study, conducted by Wageningen Livestock Research at the request of EFPRA, in which the effect of partially replacement of soybean meal by two different processed animal proteins (PAPs) of pig origin on performance results, intestinal health, litter quality, footpad lesions and bone quality in broilers chickens from 0 – 42 days was evaluated. The two PAPs differ from each other in processing method. From this study it was concluded that it is possible to replace a part of the dietary soybean meal by processed proteins from pig origin, while maintaining performance results, litter quality, footpad health, gait, intestinal health and bone quality.

1. An experiment was conducted to evaluate the effects of technical feed ingredients between 14 and 28 d of age on performance and health status of broilers (d 14–35) fed diets with a high inclusion rate of rapeseed meal as a nutritional challenge. It was hypothesized that the feed ingredients would improve health status related parameters. 2. A total of 1008 one-day-old male Ross 308 chicks were distributed over 36 floor pens and allocated to one of six iso-caloric (AMEN 13 MJ/kg) growing diets (d 15–28): a control and five test diets supplemented with quercetin (400 mg/kg), oat hulls (50 g/kg), β-glucan (100 mg/kg), lysozyme (40 mg/kg) or fish oil ω-3 fatty acids (40 g/kg), with six replicate pens per treatment. 3. Dietary inclusion of oat hulls and lysozyme resulted in a reduction in broiler performance during the first week after providing the experimental diets. 4. No effect of interventions on the microbiota diversity in the jejunum and ileum was observed. Ileal microbiota composition of birds fed oat hulls differed from the other groups, as shown by a higher abundance of the genus Enterococcus, mainly at the expense of the genus Lactobacillus. 5. In the jejunum, villus height and crypt depth of lysozyme-fed birds at d 28 were decreased compared to the control group. Higher total surface area of villi occupied by goblet cells and total villi surface area in jejunum (d 21 and 28) were observed in chickens fed oat hulls compared to other groups. 6. Genes related to the growth-factor-activity pathway were more highly expressed in birds fed β-glucan compared to the control group, while the genes related to anion-transmembrane-transporter-activity pathway in the quercetin- and oat hull-fed birds were less expressed. The genes differently expressed between dietary interventions did not seem to be directly involved in immune related processes. 7. It was concluded that the tested nutritional interventions in the current experiment only marginally effected health status related parameters.

An experiment with 288 male (Ross 308) 1-d-old broilers was conducted to test the hypothesis that a coarse diet supplemented with butyric acid (BA) and fermentable carbohydrates (FC) improves performance of broilers with a poorly digestible protein source. The interaction effects of diet structure (fine or coarse), FC supplementation (with or without), and BA supplementation (with or without) in a poorly digestible diet based on rapeseed meal (RSM) were tested in a factorial arrangement of 8 (2 × 2 × 2) dietary treatments. The coarseness of the diet affected feed intake (FI) (P < 0.001), BW gain (P = 0.001), and the feed conversion ratio (FCR) (P = 0.001) positively. Broilers fed the coarse diets had, on average, 14% heavier gizzards and 11, 7, 5, and 6% lower relative empty weights of the crop, duodenum, jejunum, and ileum, respectively, compared with those fed the fine diets. Dietary coarseness resulted in, on average, 6% greater ileal protein digestibility, 20% lower gizzard pH, 19% greater villus height, 18% lower crypt depth, and 23% reduced cecal branched chain fatty acids (BCFA) compared with chickens fed the fine diets. Broilers fed BA-supplemented diets had an improved FCR (P = 0.004) and decreased crypt depth (P < 0.001) compared with those fed diets without BA. Fermentable carbohydrate supplementation did not influence growth performance, gut development, or contents of total BCFA and total biogenic amines in the cecal digesta (P > 0.05). Supplementation with FC, however, decreased the cecal concentration of spermine by approximately 31% compared with broilers fed diets without FC (P = 0.002). In conclusion, feeding a coarse diet supplemented with BA improved performance of broilers fed a diet containing a poorly digestible protein source. The negative effects of a poorly digestible protein source can thus be partly counterbalanced by coarse grinding and BA supplementation in the diet.

A broiler study was performed to determine the pre-cecal phosphorus (P) digestibility of 5 P sources, 3 from animal (Delfos, Calfos, and porcine bone meal) and 2 of inorganic (monocalcium phosphate [MCP] and dicalcium phosphate [DCP]) origin. Delfos is processed from bones resulting in a dicalcium phosphate product, and Calfos is processed from bones in which part of the gelatin is removed but in which the hydroxy-apatite matrix is preserved. During the first 14 d, birds were housed in floor pens bedded with wood shavings and received a commercial starter diet. At d 14, broilers were randomly assigned to pens (0.9 m2, 10 birds/pen) with a slatted floor. From d 14 onwards, one of the 6 experimental diets (a basal diet, and 5 diets containing the P sources) was provided. Test diets were replicated 6 times, and the basal diet 8 times. Electron microscopy images of test products were made in order to verify whether the spatial structure of the test products could be related to the pre-cecal P digestibility of the same products. Diets met or exceeded CVB (2011) requirements for all nutrients except for P and were formulated to contain a calcium to total P ratio of between 1.4 and 1.6 and a minimal amount of phytate P. Diets contained 5 g/kg titanium oxide as a marker to determine digestibility of P. At d 24 all birds were euthanized, after which the content of the terminal part of the ileum was sampled. The P digestibility was calculated by linear regression according to World's Poultry Science Association (WPSA) protocol for determination of pre-cecal P digestibility. Pre-cecal P digestibility of MCP, DCP, Delfos, Calfos, and porcine bone meal was 88.5, 82.4, 94.5, 86.9, and 78.2%, respectively. Based on visual inspection of electron microscopy images of test products, the spatial structure of the test products might be related to P digestibility. It is concluded that processing of bone meal increases the pre-cecal P digestibility in broilers.

To sustainably contribute to food security of a growing and richer world population, livestock production systems are challenged to increase production levels while reducing environmental impact, being economically viable, and socially responsible. Knowledge about the sustainability performance of current livestock production systems may help to formulate strategies for future systems. Our study provides a systematic overview of differences between conventional and organic livestock production systems on a broad range of sustainability aspects and animal species available in peer-reviewed literature. Systems were compared on economy, productivity, environmental impact, animal welfare and public health. The review was limited to dairy cattle, beef cattle, pigs, broilers and laying hens, and to Europe, North America and New Zealand. Results per indicators are presented as in the articles without performing additional calculations. Out of 4171 initial search hits, 179 articles were analysed. Studies varied widely in indicators, research design, sample size and location and context. Quite some studies used small samples. No study analysed all aspects of sustainability simultaneously. Conventional systems had lower labour requirements per unit product, lower income risk per animal, higher production per animal per time unit, higher reproduction numbers, lower feed conversion ratio, lower land use, generally lower acidification and eutrophication potential per unit product, equal or better udder health for cows and equal or lower microbiological contamination. Organic systems had higher income per animal or full time employee, lower impact on biodiversity, lower eutrophication and acidification potential per unit land, equal or lower likelihood of antibiotic resistance in bacteria and higher beneficial fatty acid levels in cow milk. For most sustainability aspects, sometimes conventional and sometimes organic systems performed better, except for productivity, which was consistently higher in conventional systems. For many aspects and animal species, more data are needed to conclude on a difference between organic and conventional livestock production systems.

De studie beschreven in dit rapport had tot doel voor een aantal specifieke onderdelen van de berekening van de stalbalans na te gaan of de berekening van de stikstofexcretie voor varkens en pluimvee aansluit bij de biologische productie van varkens en leghennen in de praktijk. Hiervoor is in een deskstudie aandacht besteed aan de stikstof- en fosforgehalten in eigen geteelde biologische voedermiddelen, de berekening van het levend eindgewicht van biologische vleesvarkens en de invloed van biologische huisvesting op gasvormige verliezen bij pluimvee en varkens. Daarnaast zijn stalbalansen verzameld van biologische bedrijven met leghennen, vleesvarkens en zeugen. Hiermee zijn de bruto excretie van N en P en de gasvormige N-verliezen berekend. Op basis van de resultaten worden aanbevelingen gedaan voor praktische toepassing.

In this study, the usefulness of intrinsic phytase of plant ingredients for degrading phytate was investigated. The enzymatic conversion from phytate to soluble inorganic phosphate was determined in vitro with and without addition of microbial phytase. Phytate degradation was measured in mixtures in which ingredients with a high intrinsic phytase activity and ingredients with a high phytate content were combined. In deze studie is de bruikbaarheid van intrinsiek fytase vanuit grondstoffen voor de afbraak van fytinezuur in grondstoffen onderzocht. De enzymatische omzetbaarheid van fytinezuur naar oplosbaar anorganische fosfaat werd in vitro bepaald met en zonder toevoeging microbieel fytase. De afbraak van fytinezuur is gemeten in combinaties van grondstoffen met een hoge intrinsieke fytase activiteit en grondstoffen met een hoog fytinezuurgehalte.

The aim of this study, comprising two experiments, was (1) to determine in Experiment 1 the relationship of incremental dietary P (phosphorus) content on precaecal digestible P in male broilers and (2) to determine in Experiment 2 the precaecal P digestibility of various inorganic P sources at marginal levels of P supply.In Experiment 1, a total of 260 male Ross 308 broilers were divided into groups of 10 birds per pen resulting in 8 replicates for treatment 1 and 6 replicates for treatments 2–4. Experimental diets were formulated to contain 4 incremental concentrations of digestible P by means of increasing concentrations of monocalcium phosphate (MCP). In the second experiment, 480-d-old male Ross 308 broilers were divided in groups of 12 birds per pen resulting in 16 replicates for the basal diet and 6 replicates for each test diet. A total of 4 inorganic P sources, MCP, monodicalcium phosphate (MDCP), dicalcium phosphate (DCP) and defluorinated phosphate (DFP) were added to the basal diet to determine the precaecal P digestibility. Three of the 4 inorganic P sources (MCP, MDCP and DCP) represented a mix of batches from different producers. At the end of both experiments, the chyme of the posterior part of the small intestine was collected. Digestibility of P and Ca was determined using titanium dioxide as indigestible marker.In Experiment 1, a reduction in precaecal digestibility of P was observed above an estimated precaecal digestible dietary P concentration of 4.8 g/kg.The precaecal P digestibility of the tested inorganic P sources in Experiment 2 was 78.3% for MCP, 59.0% for DCP, 70.7% for MDCP and 31.5% for DFP.

Sustainable livestock production systems are needed to feed the larger, more urban, richer and older world population in 2050. Quantitative information about the sustainability performance of existing livestock production systems can aid the debate of which actions could be developed and implemented. Strong points of conventional and organic dairy cattle, beef cattle, pig, laying hen, and broiler production systems were identified in peer-reviewed literature for a limited number of sustainability indicators within the subjects of economy, productivity, environment, animal welfare, and public health. This study aims to identify lessons learned for sustainable livestock production.

The purpose of this experiment was to evaluate the effects of five nutritional interventions, provided during d 14 – 28, including inclusion of a plant extract (quercetin); an insoluble fiber (oat hulls); a prebiotic (β- glucan); an anti-microbial protein (lysozyme), and ω-3 fatty acids from fish oil, on growth performance, composition of the intestinal microbiota, and morphology and gene expression of small intestine of broilers. Despite the different types of interventions, parameters related to immune competence were only marginally affected by the tested products. It seemed that in this study inclusion of oat hulls, and probably β-glucans, had perspective to improve immune competence. It is recommended to revaluate some of the tested interventions, especially dietary inclusion of oat hulls and β-glucans, in broilers starting from day-old onward.

1. The main dietary challenge in organic laying hen production is to fulfil the digestible methionine (MET) requirement in a diet consisting of ingredients of organic origin only. 2. The aim of the present experiment was to determine the response of organic housed laying hens (26-34 weeks of age) to dietary energy and MET during a summer and winter trial. Per trial, a total of 128 17-week-old Brown Nick hens were allotted to 16 pens, which were connected to an outdoor run. Each experiment comprised 8 dietary treatments according to a 4 × 2 factorial design. The factors were AFD MET level (2.3, 2.7, 3.1 and 3.5 g/kg) and energy content (10.9 and 12.1 MJ). 3. Dietary energy content did not affect energy intake (1361 kJ/d) in summer, whereas energy intake in winter was increased in hens that were fed on the 12.1-MJ diets (1514 vs. 1421 kJ/d). Maximal egg mass in summer was achieved if a diet with 3.5 g/kg MET was given, corresponding to a digestible MET intake of 421 mg/d. During winter, maximal egg mass was achieved with a digestible MET intake of 360 mg/d, which was already realised with a MET content of 2.7 g/kg. 4. Because digestible MET content for maximal egg performance differed between the summer and winter trial, dietary energy to MET ratio might be adjusted to seasonal conditions.

The objective of this study was to determine the effects of different growth patterns and dietary crude protein levels during rearing in broiler breeder females on fertility, hatchability, embryonic mortality, and offspring performance. A 2 × 3 factorial arrangement of treatments was used, with 2 growth patterns to reach a target body weight at 20¿wk of age of 2,200 g (standard = standard growth pattern) or 2,400 g (high = high growth pattern), and 3 dietary protein levels (high = crude protein, high), (medium = crude protein, medium), and low = crude protein, low). Fresh egg composition and organ development in hatchlings were determined. Offspring of the different groups were reared until an age of 34 d and feed intake, body weight gain, mortality, and carcass composition were determined. In 29-wk-old high growth pattern breeders compared to standard growth pattern breeders, fertility and hatchability of set eggs were increased; embryonic mortality between d 1 and 9 was decreased whereas hatchability of fertile eggs was not affected. Breeders fed the medium crude protein diet showed a decreased hatchability of fertile eggs caused by an increased embryonic mortality between d 18 and 21 compared to breeders fed the high crude protein and low crude protein diets. Offspring of 29-wk-old high growth pattern breeders tended (P = 0.059) to have a higher body weight at d 34 than offspring of standard growth pattern breeders, which was achieved by a tendency to a higher body weight gain (P = 0.057). Offspring of breeders fed the medium and low crude protein diet showed a higher feed intake between d 18 and 27 and during the total growth period, as compared to offspring of high crude protein breeders. Male broilers of low crude protein breeders had higher breast meat yield than male broilers of high crude protein breeders, while breast meat yield of female broilers was not affected by dietary protein levels. This experiment showed that a higher growth pattern during the rearing period increased fertility, decreased embryonic mortality, and improved offspring performance in young breeders, whereas decreased dietary protein level had no or less pronounced effects on these traits.

High growth rates in modern-day broilers require diets concentrated in digestible protein and energy. In addition to affecting feed conversion efficiency, it is important to prevent surplus dietary protein because of greater amounts of undigested protein entering the hindgut that may be fermented by the resident microbiota. The latter may result in increased formation of a wide range of protein-derived compounds including ammonia, amines, indoles and phenols, in addition to secondary products (lactate, succinate) and gases such as methane, hydrogen and carbon dioxide. In poultry, studies have shown the presence of protein fermentation products such as biogenic amines and branched chain fatty acids (BCFA) in the ileal and caecal digesta. The production and metabolism of nitrogenous waste products (as a result of protein fermentation) such as uric acid and ammonia may lead to a burden on the organism and cause additional energy losses. Although biogenic amines are important for normal gut development, greater concentrations may cause gizzard erosion, mortality and depressed growth rate in broilers. A decrease in indigestible protein reduces hindgut protein fermentation. In broilers, feeding diets with coarse particles (between 600 to 900 µm) and/or using feed additives, such as pre- and probiotics and organic acids, especially butyric acid, may improve protein digestion, thereby, potentially reducing hindgut protein fermentation. Studies are therefore needed to determine the extent and importance of hindgut protein fermentation on performance and gut health in broilers.

The world population is growing, and improving living standards and urbanisation are driving factors in the global increase in meat, egg and milk consumption (Boland et al., 2013). Poultry production is a key factor in providing sufficient animal protein. To achieve efficient poultry production, highly digestible diets need to be fed, often resulting in competition for resources for human consumption (the food-feed competition). This intensifies the search for novel dietary ingredients that neither compete for resources, nor for arable land and freshwater. Seaweed is such a novel dietary ingredient of interest. This thesis describes studies into the nutritional value of various seaweed species (an alternative protein source), with a focus on nutritional composition, digestibility and health in broiler chickens.In Chapter 2 the composition of intact seaweeds obtained from coastal waters in Northwestern Europe were studied as source of macronutrients for livestock. The chemical composition, in vitro digestibility and in vitro gas production were determined. The seaweed species included in this study were brown: Saccharina latissima, Laminaria digitata and Ascophyllum nodossum, red: Palmaria palmata and Chondrus crispus, and green: Ulva lactuca. The nutrient content was highly variable between and within species. Based on the protein content and amino acid pattern, intact P. palmata and U. lactuca could be a valuable protein source for farm animals, with the high non-starch polysaccharides and non-protein nitrogen contents and a low in vitro digestibility potentially limiting their use as a feed ingredient for monogastric species. Furthermore, the fermentability of L. digitata, S. latissima and P. palmata indicate that these intact seaweeds may have a higher nutritional value in ruminants. The high ash content hampers the use of intact seaweed for both ruminants and simple stomached animal species.To be able to include seaweed in broiler diets, the ash content needs to be reduced and the digestibility and shelf life increased. In Chapter 3, the effects of ensiling, washing and extraction processes were evaluated using S. latissima, L. digitata and U. lactuca incubations in an in vitro simulated digestibility model. In an in vivo study, broilers were fed S. latissima silage or silage residue. Washing and ensiling reduced the ash content, but also the in vitro organic matter digestibility. Washing reduced in vitro nitrogen digestibility. Extraction processes decreased in vitro organic matter and nitrogen digestibility. Feeding seaweed diets to broilers resulted in a higher feed conversion ratio (FCR), without increasing body weight (BW). Feeding S. latissima silage residue compared to silage resulted in a slightly better broiler performance and a higher pre-caecal amino acid digestibility. In conclusion, washing, ensiling and extraction processes reduced the nutritional value of the seaweed products, and did not make seaweed suitable for inclusion in broiler diets. To create suitable seaweed products for inclusion in broiler diets, a further reduction in the ash content and increase in digestibility are necessary.To increase the economic viability of the use of seaweed in livestock diets, products resulting from a biorefinery approach can be included in broiler diets. To investigate methods to improve seaweed digestibility, Chapter 4 discusses the effects of a proteolytic enzyme pre-treatment of green seaweed species U. laetevirens and red seaweed species Solieria chordalis co-products, resulting from a biorefinery process, before inclusion in a broiler diet. Broilers were fed diets including U. laetevirens or S. chordalis co-products, with or without proteolytic enzyme pre-treatment of the seaweed. The seaweed diets increased BW gain, and feed intake in the third week of the experiment. Birds fed the U. laetevirens compared to the S. chordalis diets had a higher BW gain, and a lower FCR. Seaweed inclusion reduced diet digestibility. Birds fed U. laetevirens vs. S. chordalis diets had shorter villi. Untreated versus treated seaweed in the diets led to lower plasma Interleukin-13 levels. In conclusion, the proteolytic enzyme treatment of the seaweed co-products did not improve performance or health-related parameters, and reduced digestibility of the diets. U. laetevirens co-product inclusion did improve performance based on growth and FCR. It had a slight negative effect on duodenal villus length, and a positive effect on crypt depth. The inflammation response was strongly reduced in birds fed the untreated U. laetevirens diet, making the U. laetevirens co-product of interest for further research.The experiment described in Chapter 5 investigated a proteolytic enzyme pre-treatment to improve digestibility of U. laetevirens seaweed biorefinery co-products when included in a standard diet or a diet based on European protein sources. The effects on health and performance were further investigated. Broilers were fed a soy or EU-based diet, including the U. laetevirens co-product treated without or with a proteolytic enzyme. In the last two weeks, birds fed the soy vs. EU-based grower diets showed a higher BW, BW gain and feed intake, as well as a lower FCR in wk 3. Heavier gizzards and more gizzard contents were observed in birds fed the EU vs. soy-based diets, as well as longer villi. U. laetevirens supplemented diets had a higher water holding capacity than the basal diets. Enzyme treatment did not affect nutrient digestibility. U. laetevirens inclusion in soy-based diets led to higher, and in EU-based diets to lower apparent pre-caecal digestibility of all nutrients. Dietary U. laetevirens inclusion had different effects when added to a soy or EU-based diet. No obvious health effects were observed, leading to a conclusion of the absence of performance of health promoting bioactive components in the U. laetevirens co-product, or of diminishing of these effects due to the proteolytic enzyme pre-treatment.In the final Chapter 6 the potential of seaweed for broiler nutrition is discussed based on its nutritional composition and the effects on digestibility, performance and health. The water holding capacity and viscosity of seaweed are discussed, as well as the limitations and future of seaweed for broiler nutrition. The potential of seaweed as dietary ingredient for broilers is discussed, in light of a biorefinery approach and seaweed availability. Recommendations for further research are presented, as well as implications of this research for the industry, finalized by the conclusions drawn from this thesis.&nbsp

Improving dietary phosphorus (P) absorption and retention has been intensively studied in pig and poultry due to the low digestibility of inositol phosphate (IP), global mineral P scarcity and increasing public concerns over environment pollution. The main aim of this thesis was to provide novel insights into calcium (Ca) and P absorption, metabolism and retention in pigs and poultry.The impact of dietary Ca content with or without microbial phytase supplementation on Ca and P absorption/solubilization in different digestive tract segments was studied in pigs. Increasing dietary Ca content reduced apparent P digestibility in all digestive tract posterior to stomach, and this impact was greater for the phytase supplemented diets in the distal ileum. Moreover, incremental dietary Ca content reduced P solubility, accompanied with a reduced IP6 degradation in the distal ileum. Thus dietary Ca reduced P absorption via reducing IP6 degradation and precipitation of P, which was more pronounced in microbial phytase included diets. Furthermore, a high dietary Ca content reduced mRNA expression of Ca-related transporters in the colon and jejunum, while it increased mRNA expression of Ca-related claudins in the jejunum. These results indicated that increasing dietary Ca supply switched Ca absorption from transcellular to paracellular pathway. In addition to that, dietary Ca reduced mRNA expression of Ca-related transporters and claudins in the kidney, suggesting that kidney played a central role in Ca and P homeostasis.In contrast to pigs, the negative impact of dietary Ca on P absorption was less pronounced in broilers fed diets supplemented with microbial phytase. Microbial phytase supplementation also increased Ca absorption particularly in the low-Ca diets. However, this positive impact was insufficient to restore the negative effect of Ca deficiency on growth performance or tibia breaking strength. Moreover, incremental dietary Ca supply reduced mRNA expression of both Ca-related transporters and claudin in the duodenum, while upregulated their expression in the kidney. These results suggested that kidney might not play a central role in Ca and P homeostasis.The impact of limestone particle size and inclusion level on Ca and P absorption was studied in broilers. Fine was more digestible than coarse limestone in the jejunum, but this difference disappeared in the ileum particularly at a low Ca intake. Irrespective of limestone particle size, minimal requirement of Ca/P was 1.00-1.25 to optimize Ca and P digestibility without compromising tibia breaking strength. Moreover, P digestibility in the ileum was gradually decreased with incremental Ca intake. The P solubility in the crop, gizzard and jejunum, however, was not affected by limestone particle size or inclusion level. Furthermore, mRNA expression of P-related transporter in both duodenum and jejunum was downregulated with increasing Ca intake. Thus Ca-induced downregulation of P transporter was an important mechanism by which dietary Ca reduced P absorption. Apart from that, mRNA expression of Ca- and P-related transporters in the duodenum was downregulated by dietary Ca intake in a limestone particle size dependent manner.In conclusion, in pigs incremental dietary Ca content reduces intestinal P absorption via hampering IP degradation and precipitation of P, with a larger impact in microbial phytase-supplemented diets. Increasing dietary Ca content shifts intestinal Ca absorption from transcellular to paracellular pathway, and kidney plays a central role in whole body Ca homeostasis. By contrast, in broilers incremental dietary Ca content reduces intestinal P absorption, which was more pronounced in phytase-free diets. Furthermore, Ca-induced downregulation of P transporters is an important mechanism by which dietary Ca reduces intestinal P absorption. Overall, insights obtained in poultry studies cannot be extrapolated to pigs and vice verse when it comes to Ca and P homeostasis.