Effects of dietary crude protein level on odour from pig manure

The objective of this study was to determine the effects of dietary crude protein (CP) level on odour emission, odour intensity, hedonic tone, and ammonia emission from pig manure and on manure composition (pH, total nitrogen, ammonium, volatile fatty acids, indolic, phenolic and sulphur-containing compounds). An experiment was conducted with growing pigs (n = 18) in a randomised complete-block design with three treatments in six blocks. Treatment groups were 12%, 15% and 18% CP diets. Barley was exchanged for soya-bean meal. Crystalline amino acids (AA) were included in the 12% CP diet up to the level of pigs' requirement; the same amount of AA was added to the 15% and 18% CP diets. Pigs with an initial body weight (BW) of 36.5 ± 3.4 kg (mean ± s.d.) were individually penned in partly slatted floor pens and offered a daily feed allowance of 2.8 × maintenance requirement for net energy (NE: 293 kJ/kg BW^0.75). Feed was mixed with water, 1/2.5 (w/w). Faeces and urine of each pig were accumulated together in a separate manure pit under the slatted floor. After an adaptation period of 2 weeks, the manure pits were cleaned and manure was collected. In the 5th week of the collection period, air samples for odour and ammonia analyses, and manure samples were collected directly from each manure pit. Air samples were analysed for odour concentration and for hedonic value and intensity above odour detection threshold. Manure samples were analysed for volatile fatty acids, and indolic, phenolic and sulphurous compounds, ammonium and total nitrogen concentrations. Reducing dietary CP from 18% to 12% lowered odour emission ( P < 0.05) and ammonia emission ( P = 0.01) from pig manure by 80% and 53%, respectively. Reduced dietary CP decreased total nitrogen, methyl sulphide, carbon disulphide, ethanethiol, phenol, 4-ethyl phenol, indole and 3-methyl indole concentrations in the manure ( P < 0.05). Volatile fatty acids and cresols concentrations in the manure of pigs fed different dietary CP levels were similar. A reduction of dietary CP and at the same time providing essential AA is an option to reduce odour emission as well as ammonia emission from pig manure.     

The influence of diet crude protein level on odour and ammonia emissions from finishing pig houses

Feed trials were carried out to assess the influence of crude protein content in finishing pig diets on odour and ammonia emissions. Eight pigs (4 boars and 4 gilts), average initial weight 70.8 kg (s.e. 3.167) were housed in two pens that were isolated from the rest of a pig house at University College Dublin Research Farm, Newcastle, Dublin, Ireland. Four diets containing 130, 160, 190 and 220 g x kg(-1) crude protein were fed during six four-week feeding periods (one treatment per room). The first week of the feeding periods served to allow odour build up in the pens and as a dietary adjustment period. The pens had partially slatted floors that were cleaned and had all the manure removed after each four-week period. Odour and ammonia concentrations were measured on days 9, 14, 16, 21 and 23 of each trial period. Odour samples were collected in Nalophan bags and analysed for odour concentration using an ECOMA Yes/No olfactometer. The odour threshold concentration was calculated according to the response of the olfactometry panel members and was displayed in Ou(E)m(-3), which referred to the physiological response from the panel equivalent to that elicited by 40 ppbv(-1) n-butanol evaporated in 1 m(3) of neutral gas. Ammonia concentrations in the ventilation air were measured using Dr?ger tubes. The odour emission rates per animal for the 130, 160, 190 and 220 g x kg(-1) crude protein diets were 12.1, 13.2, 19.6 and 17.6 Ou(E)s(-1)animal(-1), respectively (P<0.01). The odour emission rate per livestock unit (500 kg) for the 130, 160, 190 and 220 g x kg(-1) crude protein diets were 77.6, 80.0, 115.8 and 102.9 Ou(E)s(-1)LU(-1), respectively (P<0.01). The ammonia emission rates per animal for the 130, 160, 190 and 220 g x kg(-1) crude protein diets were 3.11, 3.89, 5.89 and 8.27 g x d(-1)animal(-1), respectively (P0.05). Manipulation of dietary crude protein levels would appear to offer a low cost alternative, in relation to end-of-pipe treatments, for the abatement of odour and ammonia emissions from finishing pig houses.     

Effect of crude protein concentration and sugar-beet pulp on nutrient digestibility, nitrogen excretion, intestinal fermentation and manure ammonia and odour emissions from finisher pigs

A 2 × 2 factorial experiment was conducted to investigate the interaction between high and low dietary crude protein (CP) (200 v. 150 g/kg) and sugar-beet pulp (SBP) (200 v. 0 g/kg) on nutrient digestibility, nitrogen (N) excretion, intestinal fermentation and manure ammonia and odour emissions from 24 boars (n = 6, 74.0 kg live weight). The diets were formulated to contain similar concentrations of digestible energy (13.6 MJ/kg) and lysine (10.0 g/kg). Pigs offered SBP-containing diets had a reduced (P < 0.05) digestibility of dry matter, ash, N, gross energy and an increased (P < 0.001) digestibility of neutral-detergent fibre compared with pigs offered diets containing no SBP. There was an interaction between CP and SBP on urinary N excretion and the urine : faeces N ratio. Pigs offered the 200 g/kg CP SBP-based diet had reduced urine : faeces N ratio (P < 0.05) and urinary N excretion (P < 0.05) compared with those offered the 200 g/kg CP diet without SBP. However, there was no effect of SBP in pigs offered 150 g/kg CP diets. Manure ammonia emissions were reduced by 33% from 0 to 240 h (P < 0.01); however, odour emissions were increased by 41% (P < 0.05) when pigs were offered SBP diets. Decreasing dietary CP to 150 g/kg reduced total N excretion (P < 0.001) and ammonia emissions from 0 to 240 h (P < 0.05). There was an interaction between dietary CP and SBP on branched-chain fatty acids (P < 0.001) in caecal digesta. Pigs offered the 200 g/kg CP SBP-containing diet reduced branched-chain fatty acids in the caecum compared with pigs offered the 200 g/kg CP diet containing no SBP. However, there was no effect of SBP in the 150 g/kg CP diet. In conclusion, pigs offered SBP-containing diets had a reduced manure ammonia emissions and increased odour emissions compared with diets containing no SBP. Pigs offered the 200 g/kg CP SBP-containing diet had a reduced urine : faeces N ratio and urinary N excretion compared with those offered the 200 g/kg CP diet containing no SBP.     

Odour and ammonia emissions from intensive poultry units in Ireland

Odour and ammonia emissions were measured from three broiler, two layer and two turkey houses in Ireland. The broiler units gave a large range of odour and ammonia emission rates depending on the age of the birds and the season. A considerable variation between the odour and ammonia emission rates was evident for the two layer units which may have been due to the different manure handling systems utilised in the houses. There was relatively little difference in the odour and ammonia emissions from the two turkey houses. As a precautionary principle, odour emission rates utilised in atmospheric dispersion models should use the maximum values for broilers and turkeys (1.22 and 10.5 ou(E) s(-1) bird(-1) respectively) and the mean value for the layers depending on the manure handling system used (0.47 or 1.35 ou(E) s(-1) bird(-1)).     

Effect of dietary crude protein on ammonia-N emission measured by herd nitrogen mass balance in a freestall dairy barn managed under farm-like conditions

The main objective of this experiment was to monitor the impact of barn side and dietary crude protein (CP) on production performance, manure production and composition, and ammonia nitrogen (N) emission from a lactating dairy herd housed in a free-stall barn and managed under farm-like conditions throughout a number of months in each season of the year. The 78-cow lactating herd of the University of Wisconsin-Platteville (USA) was halved and each group was allocated to either the north or south side of the barn and either a recommended (REC) diet with 16.7 ± 1.3% CP dry matter basis (DM) or an excess (EXC) CP diet containing 1.5 units of CP above the REC diet (18.2 ± 1.5%). In 7 months between February 2004 and January 2005, total manure collection was conducted by manual scraping of the alleys and ammonia-N emission was calculated as intake N + bedding N - milk N - scraped manure N. Side of the barn (northern v. southern exposure) did not influence measurements and there was no effect of dietary CP on dry matter intake (DMI), milk, milk fat, and milk protein production, but a lower manure N concentration was observed for the group of cows fed the REC diet compared with the EXC diet (3.43% v. 3.66% of DM). Nitrogen intake was 63 g/day lower (643 v. 706 g/day), milk N was unaffected (157 g/day), manure N was 32 g/day lower (391 v. 423 g/day), and ammonia-N emission was 34 g/day lower (93 v. 127 g/day) for the group consuming the REC diet compared with the group consuming the EXC diet. There were larger variations in measured responses among months of the year than between level of dietary CP. Wet and dry manure excretions tended to be higher, but manure pH was reduced when corn silage became unavailable and the diet included additional corn grain and alfalfa silage as the only forage source. Prediction of manure N excretion for a group of cow determined as N intake - N milk was 9% higher than current prediction equations of the American Society of Agricultural Engineers. Ammonia-N loss averaged 110 g/day per lactating cow, but ranged from 64 g/day to 178 g/day with no clear seasonal pattern. There was no clear association between barn temperature, manure temperature or manure pH and ammonia-N emission; however, intake N explained 61% of the variation in ammonia-N emission.     

Effect of decreasing dietary crude protein in fattening calves on the emission of ammonia and greenhouse gases from manure stored under aerobic and anaerobic conditions

Dietary strategies can potentially help to reduce nitrogen (N) emissions and decrease the environmental impact of beef production. This study aimed to evaluate the effects of dietary crude protein (CP) concentration on animal performance, N excretion, and manure N volatilisation of finishing Holstein animals. In a first study, 105 Holstein bulls (BW 344 ± 2.6 kg; age 252 ± 0.9 days) were allocated to eight pens to evaluate the effect of two treatments (medium (M) and low (L), which contained CP 14.5% and 12% on a DM basis, respectively) on performance, and results confirmed that dietary CP decrease did not impair animal growth. In a second study, N excretion study, 24 Holstein heifers (BW 310 ± 5.3 kg; age 251 ± 1.4 days) were distributed randomly depending on the initial BW to three treatments (high (H), M, and L, which contained CP 17%, 14.5% and 12% on a DM basis, respectively). Based on N excretion, urinary N excretion was greater (P < 0.001) in H than in M and L diets, but no differences in faecal N excretion were observed among treatments. A third study with in vitro assays under aerobic and anaerobic conditions was designed to analyse gaseous emissions (volatilisation of N and carbon, C) during the storage stage of manure. Manure, faecal and urine samples, mixed at a ratio of 1:1 (wet weight), were collected during the N excretion study (manure-H, manure-M, manure-L). Under aerobic conditions, manure-M and manure-L showed a delay of 4–5 days in manure ammonia emission compared with manure-H (P < 0.01). Total N content was lower (P < 0.01) in manure-L compared with manure-M and manure-H, but N volatilisation (percentage relative to initial N) in manure-L and manure-M was greater (P < 0.01) than in manure-H. In contrast, the anaerobic N volatilisation was 20 times greater in manure-M and 10 times greater in manure-H compared with manure-L. Under aerobic and anaerobic conditions, the emission of C, as C-CO₂ and C-CH₄, was greater in manure-L than in manure-H and manure-M. Therefore, the decrease of dietary CP concentration from 17% to 14.5% and 12% is an efficient strategy to reduce urinary N excretion by 40%, without impairing performance, and also to reduce manure N losses through ammonia volatilisation under anaerobic conditions. However, a dietary CP content of 14.5% resulted in less environmental impact than a CP content of 12.8% when also considering manure emissions under aerobic or anaerobic conditions.     

Effect of dietary crude protein levels in a commercial range, on the nitrogen balance, ammonia emission and pollutant characteristics of slurry in fattening pigs

An experiment was conducted to investigate the effect of dietary levels of crude protein (CP), close to the range used commercially and to the European Commission recommended values, on the nitrogen (N) balance, ammonia (NH(3)) emission and pollutant characteristics of the slurry from growing and finishing pigs. Three feeding programmes with different CP levels were compared during the growing and the finishing periods of fattening. Diets were formulated to be isoenergetic and for the digestible lysine : metabolisable energy ratio to be similar in all the diets for each phase, but differed in CP concentration (160, 150 and 140 g CP/kg for the growing phase and 155, 145 and 135 g CP/kg for the finishing phase). Faeces and urine from barrows (eight replicates per diet) allocated in metabolism cages were collected separately for 5 days to calculate the N balance and for 2 days to measure NH(3) emission in a laboratory system for 240 h. Excreta were analysed for pH, volatile fatty acids (VFA), total N, electrical conductivity (EC), total solids (TS), volatile solids (VS), biochemical oxygen demand (BOD(5)), chemical oxygen demand (COD) and NH(4)-N reduction of dietary CP content led to a linear decrease of urinary (P < 0.05) and total (P < 0.05) N excretion, and N excretion/feed intake (P < 0.001). The emission of NH3 was similar in all diets (P > 0.05) during the 240 h of study. However, in the growing phase, the NH(3)-N level in slurry was lower (P < 0.05) for the low-CP diet. In addition, the CP level had no significant effect (P > 0.05) on total VFA, EC, TS, VS, COD or BOD(5) contents of excreta. These parameters were higher (P < 0.05) in slurry from the finishing phase than from the growing phase. However, NH(4)-N in the slurry decreased (P < 0.05) by 20.3% and 28.4% when the CP level was decreased by 9.30 or 21.40 g/kg, respectively. It is concluded that lowering dietary CP levels even by small amounts and using CP levels close to these used in commercial diets and close to the European Commission recommended values will decrease urinary and total N excretion in the slurry of growing-finishing pigs. The slurry from finishing pigs is more concentrated than that from growing pigs.     

Estimating the requirement of dietary crude protein for growing blue-breasted quail (Excalfactoria chinensis)

Two experiments were conducted to investigate the requirement for dietary crude protein (CP) in growing blue-breasted quail (BBQ). In Experiment 1, 300 1-day-old quails were randomly assigned to 10 groups according to a 2×5 factorial arrangement of treatments with two metabolisable energy (ME) levels (12.13 and 13.39 MJ/kg) and five CP concentrations (160, 190, 220, 250 and 280 g/kg) for 8 weeks. In Experiment 2, 300 1-day-old quails were subjected to a different factorial arrangement of treatments with two ME levels (11.51 and 12.13 MJ/kg) and five CP concentrations (210, 220, 230, 240 and 250 g/kg) for 28 days. Experiment 1 revealed that an interaction existed in weight gain between ME and CP levels in weeks 1 to 4. In both ME groups, quails receiving CP of 160 g/kg showed the least weight gains (P<0.05). No differences (P>0.05) existed in weight gain between the ME groups in which quails ingested CP of 250 and 280 g/kg, whereas quails consuming CP of 220 g/kg with an ME of 13.39 MJ/kg had smaller weight gain than did those ingesting higher CP concentrations (P<0.05). Of main effects for weeks 1-4, quails treated with an ME of 12.13 MJ/kg consumed more feed than did those receiving another ME level, whereas quails in both ME treatments showed similar feed efficiencies. For weeks 5 to 8, no difference (P>0.05) in weight gain, feed intake and feed efficiency was seen regardless of ME levels, and no interaction existed between ME and CP levels. In Experiment 2, the best weight gain and feed efficiency were achieved when the dietary CP concentration was more than 210 g/kg, and quails treated with 11.51 MJ/kg showed better weight gain and feed efficiency (P<0.05) than did those that received 12.13 MJ/kg. Furthermore, the weight gains and protein intakes on the basis of per MJ from the two experiments were pooled together to estimate the protein intake necessary for the best growth performance by two mathematic models; they were then converted to dietary CP concentrations of 204 (minimum) and 233 g/kg (maximum) when ME was 11.51 MJ/kg. In conclusion, BBQ will achieve good growth performance with dietary CP of more than 204 g/kg on the basis of an ME of 11.51 MJ/kg in weeks 1 to 4.     

Effect of increasing inclusion rates of tofu by-product in diets of growing pigs on nitrogen balance and ammonia emission from manure

To reduce competition with human-edible feed resources, it is of interest to incorporate by-products from the food industry in animal feeds. The current research investigated the effect of including increasing amounts of tofu by-product (TF) in practical pig diets on animal performance, nitrogen balance and ammonia emissions from manure. Two experiments were conducted including a control diet without TF, containing 160 g/kg dietary non-starch polysaccharides (NSPs) and three diets including 122, 246 and 360 g TF/kg DM (TF122, TF246 and TF360, respectively) to reach 220, 280 and 360 g/kg NSP. All diets had the same level of CP and protein digestible in the small intestine which particularly was realized by replacing rice bran with TF. Animal performance was assessed in a first experiment with 40 growing barrows with initial BW of 26.6 ± 1.80 kg (M ± SD) being allocated to the 4 treatments, during 2 growth phases (i.e. until 50 kg BW and from 50 to 80 kg BW). In the growth phase until 50 kg, feed intake and average daily gain (ADG) were linearly reduced by dietary TF inclusion, while this negative impact disappeared during the second growth phase (50 to 80 kg BW). Tofu by-product inclusion even positively affected the feed conversion ratio during this second growth phase (3.4 to 2.7 kg feed/kg ADG for 0 to 360 g/kg dietary TF). Over the entire growth period, performance and feed intake were negatively affected at the highest dietary TF level. Experiment 2 was conducted to assess digestibility, nitrogen balance and ammonia emission from manure. For this purpose, 16 pigs with BW of 62.8 ± 3.6 kg (M ± SD) were assigned to either 1 of the 4 treatments. There was no difference in total tract apparent digestibility of dietary organic matter or CP, while NDF digestibility increased with increasing TF level, suggesting increasing importance of the hindgut fermentation when digesting diets with increasing TF levels. Nevertheless, this was not reflected in increasing levels of faecal volatile fatty acids or purines, nor in reduced manure pH. As a result, ammonia emission from slurry was not reduced through dietary TF inclusion, despite the linear decrease in urinary nitrogen. In conclusion, TF can be included in pigs’ diets up to an inclusion rate of 25% without risk of impaired animal performance; however, this dietary strategy fails to mitigate ammonia emission from slurry.     

The effect of cereal type and enzyme addition on pig performance, intestinal microflora, and ammonia and odour emissions

Two 2 × 2 factorial experiments were conducted to investigate the interaction between cereal type (wheat v. barley) and exogenous enzyme supplementation (with or without) on odour and ammonia emissions (experiment 1) and growth performance (experiment 2) in grower-finisher pigs. The enzyme supplement used contained endo-1, 3 (4) - β- glucanase (EC 3.2.1.6) and endo-1, 4 - β-xylanase (E.C 3.2.1.8). The diets were formulated to contain similar levels of net energy (9.8 MJ/kg) and lysine (10.0 g/kg). The experimental treatments were as follows: (1) wheat-based diet, (2) wheat-based diet containing a β-glucanase and β-xylanase mixed enzyme supplement, (3) barley-based diet and (4) barley-based diet containing a β-glucanase and β-xylanase mixed enzyme supplement. In experiment 1, the diets were offered to the pigs for 23 days in sealed pens (eight pigs per pen) and this was repeated four times (n = 4). Odour and ammonia emissions were measured on days 9, 11, 14, 16, 21 and 23 of each replicate period. Odour samples were collected in 20-l Nalophan bags and analysed for odour concentration using an ECOMA Yes/No Olfactometer. Ammonia concentrations in the ventilation air were measured using Dräger tubes. In experiment 2, 220 pigs were group fed in mixed sex pens using single-space feeders (11 pigs per feeder, six boars and five gilts) (n = 5). There was a cereal × enzyme interaction in odour emission rates, ammonia emissions and selected microbial populations in the caecum and colon (P < 0.05). The addition of an enzyme supplement to the barley-based diet increased both odour and ammonia emission, however the addition of an enzyme to the wheat-based diet decreased ammonia emission rates and had no effect on odour emission. Pigs offered the unsupplemented barley-based diet had a significantly (P < 0.05) lower population of Enterobacteriaceae spp. and a higher population of Bifidobacteria spp. compared with enzyme-supplemented barley diets. However, there was no effect of enzyme supplementation in wheat-based diets. In the performance experiment, neither cereal type nor enzyme inclusion had an effect on pig performance or carcass characteristics. In conclusion, the inclusion of an enzyme mix to barley-based diets increased odour and ammonia emissions, while the addition of an enzyme mix to wheat-based diets decreased ammonia emissions.     

Prevention and control of losses of gaseous nitrogen compounds in livestock operations: a review

Nitrogen (N) losses from livestock houses and manure storage facilities contribute greatly to the total loss of N from livestock farms. Volatilisation of ammonia (NH3) is the major process responsible for the loss of N in husbandry systems with slurry (where average dry matter content varies between 3 and 13%). Concerning this volatilisation of NH3, the process parameters of pH and air temperature are crucial. During a period of approximately 10 years, systematic measurements of NH3 losses originating from a large variety of different livestock houses were made. One of the problems with NH3 emissions is the large variation in the measured data due to the season, the production of the animals, the manure treatment, type of livestock house, and the manure storage. Generally speaking, prevention and control of NH3 emission can be done by control of N content in the manure, moisture content, pH, and temperature. In houses for growing pigs, a combination of simple housing measures can be taken to greatly reduce NH3 emissions. In houses for laying hens, the control of the manure drying process determines the emission of NH3. Monteny has built an NH3 production model with separate modules for the emission of the manure storage under the dairy house and the floor in the house. Manure spreading is also a major source of NH3 emission and is dependent on slurry composition, environmental conditions, and farm management. The effects of these factors have been employed in a model. Losses via NO, N2O, and N2 are important in husbandry systems with solid manure and straw. The number of experimental data is, however, very limited. As N2O is an intermediate product of complex biochemical processes of nitrification and denitrification, optimal conditions are the key issues in N2O reduction strategies. We may expect that in the near future the emission of greenhouse gases will get the same attention from policy makers as NH3. Sustainable livestock production has to combine low emissions of gaseous N compounds with acceptable odour emissions, low emissions of greenhouse gases, and acceptable standards of animal welfare. For the entrepreneur, the strategy must be built on the regulations, the special conditions of his farm, and what is reasonably achievable.     

Compost biofiltration of ammonia gas from bin composting

The effects of the manure compost/coconut peels on the ammonia removal efficiency were examined from dairy manure composting mixed with crop residues. The high rapid composting and manure compost biofiltration experiments consisted of three biofilter vessels with one composter. Dairy manure amended with rice hulls and sawdust was composted in 605 L pilot-scale composter using continuous aeration for 19 days. Three pilot-scale manure compost biofilter amended with media bed 500 mm in depth and 300 mm in diameter were built to clean ammonia emission from composter, respectively. The manure compost biofilter media in the three experimental vessels was using a 50:50 by weight mixture of manure compost and coconut peels (MC/CP). The ammonia concentrations at the inlet and outlet biofilter media were measured by boric acid traps as described by Hong et al. [Hong, J.H., Keener, H.M., Elwell, D.L., 1998. Preliminary study of the effect of continuous and intermittent aeration on composting hog manure amended with sawdust. Compost Science and Utilization 6 (3), 74-88]. Results indicated that the mixture of MC/CP performed well as a biofilter media and the ammonia removal efficiency was 100% for the filter depth of 500 mm.     

Effects of dietary crude protein and tannic acid on rumen fermentation,rumen microbiota and nutrient digestion in beef cattle

The objectives of the trial were to study the effects of dietary crude protein (CP) and tannic acid (TA) on rumen fermentation, microbiota and nutrient digestion in beef cattle. Eight growing beef cattle (live weight 350 ± 25 kg) were allocated in a 2 × 2 crossover design using two levels of dietary CP [111 g/kg dry matter (DM) and 136 g/kg DM] and two levels of TA (0 and 16.9 g/kg DM) as experimental treatments. Each experimental period lasted 19 d, consisting of 14-d adaptation and 5-d sampling. The impacts of dietary CP and TA on ruminal microbiota were analysed using high-throughput sequencing of 16S rRNA gene. Results indicated that no interactions between dietary CP and TA were found on rumen fermentation and nutrient digestibility. Increasing dietary CP level from 111 to 136 g/kg DM increased the ruminal concentrations of ammonia nitrogen (NH₃-N) (p < 0.01) and improved the CP digestibility (p < 0.001). Adding TA at 16.9 g/kg DM inhibited rumen fermentation and decreased the digestibility of dietary CP (p < 0.001), DM (p < 0.05) and organic matter (p < 0.01). Increasing the dietary CP level or adding TA did not affect the relative abundances of the major bacteria Firmicutes and Proteobacteria at the phylum level and Prevotella_1 and Christensenellaceae_R-7_group at the genus level, even though adding TA increased the Shannon index of the ruminal bacterial community. TA was partly hydrolysed to pyrogallol, gallic acid and resorcinol in rumen fluid and the inhibitory effects of TA on rumen fermentation and nutrient digestibility could have been resulted from the TA metabolites including pyrogallol, gallic acid and resorcinol as well as the protein-binding effect.     

Odour and ammonia emissions from intensive pig units in Ireland

Odour and ammonia emissions were measured at four intensive pig units in Ireland. Odour samples were collected on-site and analysed for odour concentration using an olfactometer. Ammonia concentrations in the exhaust ventilation air were measured using a portable sensor. The geomean odour emission rates over the four pig units were 17.2, 44.4, 4.3, 9.9 and 16.8 ou(E) s(-1) animal(-1) for dry sows, farrowing sows, first stage weaners, second stage weaners and finishers, respectively. The mean ammonia emission rates, measured at two of the units, were 12.1, 17.1, 1.4, 2.9 and 10.0 g d(-1) animal(-1) for dry sows, farrowing sows, first stage weaners, second stage weaners and finishers, respectively. In general, the odour and ammonia emission rates were comparable to those reported in literature, although some odour emission rate figures were noticeably lower for finishing pigs in this study. The variability in the data highlights the need for individual site assessment.     

Growth and hepatic acetyl coenzyme-A carboxylase activity are affected by dietary protein level in European seabass (Dicentrarchus labrax)

Two trials were undertaken with European seabass (Dicentrarchus labrax) to estimate the protein requirements for maintenance and growth as well as the effect of dietary protein level on the activity of hepatic acetyl coenzyme-A carboxylase (ACoAC). Six diets were formulated to contain graded levels of protein (from 5 to 55% crude protein (CP)) at a constant (12%) lipid level. Three other diets were also formulated to contain 35, 45 and 55% CP, but with a higher lipid level (19%). Groups of 10 individually marked fish (IBW: 100 g) and groups of 8 fish (IBW: 160 g) were used in trial I and II, respectively. Fish were fed to visual satiety and intake was recorded. At the end of both studies, whole body, liver and plasma samples were withdrawn for analyses. Growth rate was improved with increasing dietary CP level. Despite not being the object of a statistical analysis, feed efficiency tended to be enhanced at higher dietary CP level and protein efficiency ratio tended to decrease with increased protein intake. The reduction of the dietary protein/energy ratio, due to the increase of dietary lipids further improved growth and feed utilisation. Data from both experiments indicate 4.5+/-0.5 g kg(-1) d(-1) as the daily protein intake for maximum N gain and 520+/-50 mg kg(-1) d(-1) as the maintenance needs for nitrogen balance. An increase of dietary CP level, up to 25%, increased ACoAC activity. A further increase in dietary CP level (35 to 55%) did not affect liver ACoAC activity. The increase in dietary lipid level depressed significantly liver ACoAC specific activity.     

Influence of incrementally substituting dietary soya bean meal for rapeseed meal on nutrient digestibility, nitrogen excretion, growth performance and ammonia emissions from growing-finishing pigs

A completely randomised design experiment was performed to examine the effects of replacing different levels of soya bean meal (SBM) with rapeseed meal (RSM) on the growth performance, carcass characteristics, apparent nutrient digestibility, nitrogen (N) balance and manure ammonia emissions of growing-finishing pigs. Pigs (n = 336; mean live weight 42.1 kg) were assigned to one of four dietary treatments containing per kg diet: 210 g SBM; 140 g SBM and 70 g RSM; 70 g SBM and 140 g RSM; and 210 g RSM. All diets were formulated on an ileal digestible amino acid, net energy and available phosphorus basis. There was no significant treatment effect on average daily gain, feed intake, feed conversion ratio and carcass characteristics. There was a linear decrease in gross energy digestibility (p < 0.01) as RSM increased at the expense of SBM in the diet. There was a linear decrease in urinary N excretion (p < 0.01), N digestibility (p < 0.05), total N excretion (p < 0.05) and N retention (p < 0.05) with increasing levels of RSM. There was no effect of dietary treatment on manure ammonia emissions. The results of this study indicate that RSM can be used as a direct replacement for SBM with no associated depression in performance, when formulated on an ileal digestible amino acid and net energy basis. Consumption of diets containing incremental levels of RSM linearly decreased urinary N and total N excretion, reflecting the associated decrease in crude protein concentrations.     

Nitrogen utilisation by dairy cows fed diets differing in crude protein level with a deficit in ruminal fermentable nitrogen

We studied the efficiency of nitrogen utilisation by dairy cows, using three diets differing in the crude protein (CP) level but with similar deficits (10 g x kg(-1) dry matter, DM) in ruminal fermentable nitrogen. There was no difference in milk yield from the cows offered the three diets (130, 145 and 160 g CP x kg(-1) DM). The milk protein content differed between the two most extreme diets (28.9 vs. 29.9 g x kg(-1), P < 0.05), resulting in higher protein yields for the highest CP treatment (P < 0.01). The efficiency of nitrogen utilisation, calculated as the proportion of ingested nitrogen recovered in the milk, was significantly higher for the 130 g CP x kg(-1) DM diet than for the other two diets (0.37 vs. 0.33 and 0.32 respectively. P < 0.01). The different diets also resulted in different levels of nitrogen excretion into the environment (237, 270 and 330 g N x d(-1), P < 0.01). Hepatic deamination of the amino acids may have generated additional energy to enable the animal to make use of the additional nitrogen in the diet, resulting in an increase in plasma urea concentration.     

Supplementation of Poultry Feeds with Dietary Zinc and Other Minerals and Compounds to Mitigate Nitrogen Emissions—A Review

One of the environmental challenges that the poultry industry has been faced with is ammonia emission from manure. One way to reduce nitrogen excretion and emissions is supplementing dietary trace minerals to inhibit the activity of microbial uricase, a key enzyme converting nitrogen compounds in the manure into ammonia. Several dietary minerals are commercially available as economic alternatives for reducing ammonia emissions in poultry. In this review, we discuss different mineral elements including zinc as feed amendment minerals that could be used to reduce ammonia emission. Issues discussed include potential for inhibiting microbial uricase, dietary supplementation levels, growth performance, toxicity, their influence on manure nitrogen emission, and potential mineral accumulation in soil. In addition, we discuss other minerals and compounds that have the potential to reduce ammonia volatilization by inhibiting microbial uricase and growth of uric acid-utilizing microorganisms.     

Digestive enzymes and metabolic profile of Labeo rohita fingerlings fed diets with different crude protein levels

Labeo rohita, commonly called rohu is one of the most important fish species for aquaculture in India. Digestive enzyme response and metabolic profile of fingerling L. rohita to different dietary crude protein (CP) levels (viz. 25, 30, 35 and 40%) were studied in an attempt to optimize a practical diet formulation for this species. After 45 days of feeding, activity of digestive enzymes and metabolite concentrations were assayed. Amylase, lipase and alkaline phosphatase (ALP) activities were not influenced by the dietary protein, but proteolytic and acid phosphatase (ACP) activities varied (P<0.05) between the treatments. Proteolytic activity showed a second order polynomial relationship with dietary crude protein (CP) as Y = 0.0734X(2) + 4.937X - 68.37, r(2)=0.97. A positive correlation was observed between dietary CP and amylase (r(2)=0.78). All the metabolites except muscle glucose showed significant change corresponding to the dietary protein levels. Glucose and glycogen levels corresponded to the dietary carbohydrate levels. Muscle and plasma pyruvic acid increased as the crude protein in the diet increased, whereas liver pyruvic acid showed the opposite trend. Muscle protein content was not affected by dietary CP. Protein fractions in plasma (total protein, albumin and globulin) showed maximum values in 30% CP fed group. It is concluded that proteolytic activity and ACP are the major digestive enzymes responsive to dietary CP in L. rohita fingerlings. Considering the cost effectiveness of the diet, and based on liver and plasma free amino acid levels and plasma protein fractions, 30% crude protein is recommended as the optimal dietary protein for L. rohita fingerlings.     

Increasing dispensable amino acids in diets of kittens fed essential amino acids at or below their requirement increases the requirement for arginine

Summary Kittens fed diets containing 0.75 × the NRC (1986) essential amino acid requirement (EAArq) and 210 to 560g crude protein(CP)/kg diet exhibited, with increasing CP: 1) decreasing weight gain, 2) decreasing plasma arginine concentrations, 3) increasing urinary orotic acid excretion, 4) increasing plasma glutamic acid concentrations, and 5) plasma isoleucine concentrations at levels that suggest a marginal isoleucine deficiency. Kittens fed a control diet (CD) containing 1.5 × EAArq and 350 g CP/kg diet had maximal weight gains and no orotic aciduria. It was concluded that the decreased weight gain and adverse metabolic effects were caused by arginine deficiency and possibly glutamic acid toxicity induced by high dietary dispensable amino acids. Kittens fed the diets containing 1.0 × EAArq and 350 and 560 g CP/kg diet had depressed plasma arginine and elevated glutamic acid concentrations and orotic aciduria. These results indicate that 10 g arg/kg diet is not adequate at CP concentrations above 280 g/kg and the calculated requirement of arginine is (0.02 g arginine/g CP) × (Y g CP/kg diet) + (4.0 g arginine/kg diet) where Y is the dietary CP level.Abbreviations CD control diet - CP crude protein (g CP/kg diet = g nitrogen/kg diet × 6.25) - DAA dispensable amino acids - EAA essential amino acids - EAArq essential amino acid requirement