Refining the metabolisable energy value of field beans for turkeys.

1. This study examined the feeding value of ten UK grown field bean (Vicia faba L. var. minor) cultivar samples from the same harvest year on nitrogen corrected apparent metabolisable energy (AMEn) and nutrient retention coefficients when fed to young female turkeys.2. A balancer feed (BF) was formulated to contain 12.39 MJ/kg ME and 269 g/kg crude protein. Ten nutritionally complete, mash diets were prepared by mixing 200 g/kg of each ground field bean cultivar with 800 g/kg of the BF, totalling eleven diets. Diets were fed to female BUT Premium turkeys from 40 to 50 d of age. Each diet was fed to eight raised floor pens, housing two birds, following randomisation. The AMEn was determined by the total collection technique over the last 4 d of the study. Relationships were examined between AMEn, chemical composition and quality variables of the field bean samples.3. The overall determined AMEn value of the beans ranged from 7.72 MJ/kg DM to 9.87 MJ/kg DM, giving an average AMEn of 8.80 MJ/kg DM (P < 0.05). The soluble non-starch polysaccharide (NSP) content of the beans negatively correlated with their determined AMEn (r = -0.730; P < 0.05). Bean flour lightness-darkness degree (L*) correlated positively with the AMEn (r = -0.643; P < 0.05)4. A positive correlation was observed between the degree of yellowness-blueness of bean flour and condensed tannins content (r = 0.696; P < 0.05). Step-wise regression indicated that soluble NSP + L* of field beans provided explanatory variables suitable for estimating the AMEn value for turkeys (r2 = 0.737; P < 0.05).

Feeding guanidinoacetic acid to broiler chickens can compensate for low dietary metabolisable energy formulation.

1. This study compared the responses of broilers to diets supplemented with the same level of guanidinoacetic acid (GAA) but formulated to have different N-corrected apparent metabolisable energy (AMEn) contents. The study involved 1280, one-day-old Ross 308 broilers, in 64 pens comprising 32 pens of males and 32 pens females, (20 birds in each) aged from 0 to 42 d.2. Commercial AME levels of 12.55 MJ/kg, 12.97 MJ/kg and 13.18 MJ/kg in the starter, grower and finisher diets, respectively, were set for the positive control (PC) feed. Four dietary treatments were prepared: PC (as above); negative control 1 (NC; PC - 0.21 MJ ME /kg); NC1 + 0.06% GAA; NC2 (PC - 0.42 MJ ME/kg + 0.06% GAA). Each diet was provided in 16 pens (eight male and eight female), following randomisation.3. Overall, birds fed NC1 had lower feed intakes (FI) compared to birds fed the PC and NC2+ GAA, lower weight gain (WG) compared to all the other diets and lower final body weight than birds fed the GAA diets (P < 0.05). There was a diet x sex interaction (P = 0.039), whereby feeding NC+GAA to female birds improved feed efficiency compared to being fed NC2 and NC1+ GAA, but not in males. Birds fed diets with GAA had a higher poultry efficiency factor (P < 0.001) than those fed NC1.4. There were no effects of treatment or sex on litter moisture, footpad score, white striping, wooden breast, AMEn, dry matter and fat retention (P > 0.05). However, the diet NC1+ GAA had 11.2% higher nitrogen retention coefficient compared to the NC1 diet (P = 0.038).5. Overall, the results implied that lower performance induced by a reduction of dietary AMEn in the range of 0.21 to 0.42 MJ/kg was more than compensated by supplementing 600 g/t GAA to the feed.

Bio-processing of macroalgae Palmaria palmata: metabolite fractionation from pressed fresh material and ensiling considerations for long-term storage.

Red algae, belonging to the phylum Rhodophyta, contain an abundance of useful chemicals including bioactive molecules and present opportunities for the production of different products through biorefinery cascades. The rhodophyte Palmaria palmata, commonly termed dulse or dillisk, grows predominantly on the northern coasts of the Atlantic and Pacific Oceans and is a well-known snack food. Due to its abundance, availability and cultivation capacity, P. palmata was selected for study as a potential candidate for a biorefinery process. In addition to studying juice and solid fractions of freshly harvested P. palmata, we have investigated the novel possibility of preserving algal biomass by ensilaging protocols similar to those employed for terrestrial forage crops. In the metabolite partitioning within the solid and liquid fractions following screw-pressing, the majority of the metabolites screened for-water soluble carbohydrates, proteins and amino acids, lipids, pigments, phenolics and antioxidant activity-remained in the solid fraction, though at differing proportions depending on the metabolite, from 70.8% soluble amino acids to 98.2% chlorophyll a and 98.1% total carotenoids. For the ensiling study, screw-pressed P. palmata, with comparative wilted and chopped, and chopped only samples, were ensiled at scale with and without Safesil silage additive. All samples were successfully ensiled after 90 days, with screw-pressing giving lower or equal pH before and after ensiling compared with the other preparations. Of particular note was the effluent volumes generated during ensiling: 26-49% of the fresh weight, containing 16-34% of the silage dry matter. This may be of advantage depending on the final use of the biomass.

Destruction of Staphylococcus aureus and the impact of chlortetracycline on biomethane production during anaerobic digestion of chicken manure.

Research was undertaken to ascertain the effect on biogas potential during the anaerobic digestion of chicken manure containing Staphylococcus aureus and chlortetracycline (antibiotic) from infected chicken flocks. S. aureus is a pathogenic bacteria in chicken flocks that is usually treated with the broad-spectrum antibiotic, chlortetracycline. Veterinary antibiotics are often prescribed in the poultry sector for on-farm use at the flock level to control disease; consequently, significant quantities of antibiotics are excreted from the bird into the manure. Subsequent anaerobic digestion of this chicken manure could lead to pathogens and antibiotics affecting the digestion process. Anaerobic digestion biochemical methane potential assays were completed at 35°C for 39 days, with some assays receiving S. aureus and some receiving S. aureus and chlortetracycline. No viable S. aureus cells were detected after Day 0 of the experiment. A further experiment utilising an order of magnitude greater concentration of S. aureus demonstrated a significant reduction (>400 fold) in S. aureus within 24 h when inoculated into anaerobic digestate, with no viable S. aureus cells detected by the end of 3 days. Furthermore, the efficacy of chlortetracycline was significantly reduced when applied to anaerobic digestate compared to water alone. Total biogas yields from chicken manure were significantly lowered by the addition of S. aureus, with and without chlortetracycline. However, there was no significant difference in methane yields between treatments. The cellulose control assays showed a lag phase in methane production after receiving chlortetracycline. In comparison, the absence of a lag phase when the antibiotic were added to chicken manure may have been due to the relatively high nitrogen content of the feedstock reducing the inhibition of chlortetracycline on methanogens. Therefore, this study demonstrates that the addition of S. aureus and chlortetracycline does not have a commercially relevant effect on the digestion of chicken manure.

The temperature of storage of a batch of wheat distillers dried grains with solubles samples on their nutritive value for broilers.

1. A batch of wheat distillers dried grains with solubles (DDGS) was obtained immediately after production and was separated into 5 equal parts and placed in woven polypropylene sacks. The samples were stored under 5 different temperature conditions for 1 year as follows: kept at a constant -20°C; kept at -20°C for 24 h period and after that kept at a constant +4°C; kept at a constant +4°C only; kept at a constant +15°C; stored at ambient temperature (range of weekly mean temperatures was from +4 to +22°C). 2. Each of the 5 wheat DDGS samples was included (200 g/kg) in a nutritionally complete diet and fed to broiler chickens from 7 to 21 d of age. The chemical composition of the DDGS samples was determined at the beginning and at the end of the 1-year storage period. 3. The nitrogen corrected apparent metabolisable energy (AMEn) and the nutrient availability of each sample was measured using a total collection technique. The growth performance of birds was also determined. 4. The DDGS samples kept at a constant -20°C had higher dry matter, lower oxidation value and lower antioxidant contents. The DDGS sample that was stored at ambient temperatures had a higher AMEn than the rest of the DDGS samples. 5. The results of this experiment have shown that there can be changes in the AMEn of wheat DDGS during storage at ambient temperatures. In general, there were no serious effects of storage of DDGS on its feeding value to broiler chickens.

Does the effect of pelleting depend on the wheat sample when fed to chickens?

Experimental comparisons of the nutritional value of different wheat cultivars commonly use feeds in meal form even though the large-scale broiler producers use steam pelleted feeds. The aim of this experiment was to examine the effect of steam pelleting on the performance, dietary N-corrected apparent metabolisable energy (AMEn), total tract dry matter retention (DMR), nitrogen retention (NR) and fat digestibility (FD) coefficients, and digestive tract development of broilers fed four different wheat samples in complete diets. Four European wheat samples, with different chemical composition and endosperm characteristics, were used in a broiler experiment. The wheat samples were milled through a 5 mm screen and four basal feeds containing 670 g/kg of each selected wheat sample were mixed. The basal feeds were then split into two batches and one of them was steam pelleted resulting in eight experimental diets. Each diet was fed ad libitum to eight pens of two male Ross 308 broilers from 10 to 24 days of age. Feeding pelleted diets improved (P0.05). Feeding different wheat types and pelleting did not (P>0.05) change the development of the gastrointestinal tract of the birds. The study showed that there were differences between four wheat samples when they were fed in pelleted complete feed, but no differences were observed when fed in mash form complete diets. Research on the interaction between pelleting and wheat chemical and quality characteristics is warranted.

Growth performance and endogenous losses of broilers fed wheat-based diets with and without essential oils and xylanase supplementation.

An experiment was conducted to compare the effect of a supplementary mixture of essential oils, with and without exogenous xylanase, on performance, carcass composition, dietary nitrogen (N)-corrected apparent metabolizable energy (AMEn), dry matter retention (DMR), N retention (NR), fat digestibility (FD) coefficients, and endogenous mucin losses (measured as sialic acid, SA) when fed to broiler chickens. Three hundred male Ross 308 broilers in total were reared in floor pens from 0 to 21 d of age. Birds were fed 1 of 3 wheat-based diets: basal diet (215 g/kg CP, 12.12 MJ/kg AME) with either no additive (control diet; C) or 100 g/tonne of a standardized combination of 5% carvacrol, 3% cinnamaldehyde, and 2% capsicum oleoresin (diet XT); or a combination of XT and commercial xylanase enzyme at a rate of 100 g of XT and 2,000 units (U) of xylanase/kg (diet XYL), respectively. Each diet was randomly allocated to 10 pens with 10 birds. Feeding XT and XYL diets improved birds' growth performance (P<0.05). Birds fed XT and XYL diets had an improved caloric conversion ratio (P<0.05) and consumed 1.3 MJ less AMEn per kilogram of growth compared to birds fed the control diet only. Feeding XT improved only the dietary FD coefficient (P<0.05) compared to control-fed birds, but the dietary FD coefficient did not differ for XYL diet (P>0.05). Birds fed XYL diet excreted 35% less endogenous mucin compared to control-fed birds (P<0.05). Birds fed XT alone gained more carcass protein than the control-fed birds (P<0.05) but did not differ from the birds fed XYL diet (P>0.05). There was no indication of a negative interaction between dietary essential oils and xylanase.