Factors influencing the presence and concentration of E. coli O157 and E. coli in farm waste on six cattle farms in North-West England

Aims:  To investigate the factors influencing the presence and burden of Escherichia coli O157 in farm wastes.
Methods and Results:  Wastes from six cattle farms were screened for the presence and concentration of E. coli O157 and E. coli on three occasions over a year and waste management data were collected. Sixty-three of 878 (7·1%) samples were positive for verocytotoxigenic Escherichia coli O157 and 664/875 (75·9%) for E. coli with detectable levels greater in fresh waste than in stored waste, pasture or dirty water.
Conclusions:  The turning/stirring of stored waste and the use of more than one store (allowing longer storage times) reduced the proportion of E. coli O157 positive samples. The presence of E. coli O157 significantly reduced from a high prevalence found in fresh faeces and stored waste to lower proportions in dirty water and pasture samples. Escherichia coli O157 was only detected on pasture when waste was spread from contaminated stores the day before sampling. A high prevalence of positive E. coli O157 samples were detected when cattle were re-housed.
Significance and Impact of the Study:  These findings help to support the importance of treating and storing farm waste, as well as providing evidence for the level of dilution of E. coli O157 from fresh waste to recently spread pastures.     

Environmental impact of a salmonid farm on a well flushed marine site: I. Current and water quality

The impact of a common brown trout farm on water quality was investigated at a site well flushed by lapping and tidal current. Dissolved oxygen, suspended matter, phosphate, nitrite and nitrate were seemingly not affected by the farm. High concentrations of ammonia were clearly observed close to the raft, but rapidly vanished a short distance from it, when the fish biomass was at least 576 tonnes. At that time the nitrogen loadings from the farm were estimated at 101 kg/day. On the site, phytoplankton was similar to that of the nearby French coastal area of the English Channel, concerning generic composition (extensively dominated by diatoms) and the seasonal succession of genera. The farm did not cause any increase of faecal coliform bacteria. At this stock level, the dispersal characteristics of the farm site greatly reduced its apparent impact on the water quality.     

The effect of salmon farming on the benthos of a Scottish sea loch

The effects of waste from a salmon farm on the benthos of a fjordic sea loch on the western coast of Scotland have been studied. Within 3 m of the floating cages the sediment was highly reducing, and dissolved oxygen content of the water overlying the sediment ranged from 35 to 75% saturation. At ⩾ 15 m from the cages the sediment was oxygenated, and the dissolved oxygen content of the water overlying the sediment was 50–85% saturation. Sedimentary redox potential and dissolved oxygen content of bottom water showed a seasonal variation. The benthic fauna showed marked changes in species number, species diversity, faunal abundance, and biomass in the region of the fish farm, with four zones of effect identified. Directly beneath, and up to the edge of the cages, there was an azoic zone. A highly enriched zone, dominated byCapitella capitata (Fabricius) andScolelepis fuliginosa (Claparède), occurred from the edge of the cages out to as 8 m. A slightly enriched ″transitional ″ zone occurred at ⩽ 25 m, and a “clean” zone at distances > 25 m. This study showed that salmon farming had similar effects on the benthos as other forms of organic enrichment, but the effects were limited to a small area in the immediate vicinity of the cages     

Influence of weather on the moth catches of Helicoverpa armigera at various cotton-based agro-ecological sites

Pheromones are innate products, exploited for direct population manipulation in the trapping of precise pest density. They demonstrate feasibility and efficiency against Helicopverpa armigera at five different cotton-based agro-ecological sites: river site, vegetable farm, orchard, clean cultivation site, and forest. The data were recorded at 15–20 day intervals from 8 September 2004 to 1 December 2006. The Number of moths caught during the study period demonstrated that the vegetable farm showed the maximum population of moths per trap (0.54), followed by the orchard (0.29), forest (0.19), river (0.15), and clean cultivation site (0.12). During 2004, rainfall (in the orchard and clean cultivation site) and relative humidity (in the clean cultivation site) showed positive and significant correlation with the number of moths caught. During 2005, temperatures played a significant and positive role in population fluctuation of the pest almost at all the selected sites; the minimum temperature was recorded at the vegetable farm and the average temperature was found at the forest site. Rainfall also showed a significant and positive correlation with trapped moths in the vegetable farm, orchard, and clean cultivation site. During 2006, relative humidity showed a significant and negative correlation with the trapped population at all the sites except the river site. Rainfall showed a negative and significant correlation with the pest at the forest site. Relative humidity was the most important aspect at 8.93% causing variation in the trapped population followed by maximum temperature (5.7%), rainfall (1.63%), average temperature (0.74%), and minimum temperature (0.56%).     

Detection of a common and persistent tet(L)-carrying plasmid in chicken-waste-impacted farm soil

The connection between farm-generated animal waste and the dissemination of antibiotic resistance in soil microbial communities, via mobile genetic elements, remains obscure. In this study, electromagnetic induction (EMI) surveying of a broiler chicken farm assisted soil sampling from a chicken-waste-impacted site and a marginally affected site. Consistent with the EMI survey, a disparity existed between the two sites with regard to soil pH, tetracycline resistance (Tc(r)) levels among culturable soil bacteria, and the incidence and prevalence of several tet and erm genes in the soils. No significant difference was observed in these aspects between the marginally affected site and several sites in a relatively pristine regional forest. When the farm was in operation, tet(L), tet(M), tet(O), erm(A), erm(B), and erm(C) genes were detected in the waste-affected soil. Two years after all waste was removed from the farm, tet(L), tet(M), tet(O), and erm(C) genes were still detected. The abundances of tet(L), tet(O), and erm(B) were measured using quantitative PCR, and the copy numbers of each were normalized to eubacterial 16S rRNA gene copy numbers. tet(L) was the most prevalent gene, whereas tet(O) was the most persistent, although all declined over the 2-year period. A mobilizable plasmid carrying tet(L) was identified in seven of 14 Tc(r) soil isolates. The plasmid's hosts were identified as species of Bhargavaea, Sporosarcina, and Bacillus. The plasmid's mobilization (mob) gene was quantified to estimate its prevalence in the soil, and the ratio of tet(L) to mob was shown to have changed from 34:1 to 1:1 over the 2-year sampling period.     

Variation in growth rates of the zebra mussel, Dreissena polymorpha, within Lake Wawasee

1. Field experiments conducted in Lake Wawasee in 1995 and 1996 measured the response of shell growth of Dreissena polymorpha to environmental gradients.
2. Shell growth decreased with initial shell length in four mussel size classes ranging between 8 and 22 mm, and decreased with depth, with mussels in shallow water (<4 m) having growth rates nearly twice those of mussels in deeper water (4–7 m).
3. Growth occurred early in the spring–summer period (May–June) with relatively little shell added later in the summer (July–September), and varied significantly among sites within Lake Wawasee, but not between the 2 years of this study.
4. Rank order of sites was consistent for both years implying that environmental conditions responsible for variation in shell growth were stable within Lake Wawasee.
5. Cage design did not have a significant effect on mussel shell growth nor did the distance of growth cages above the bottom (0.5–0.75 m above the bottom versus directly on the bottom).
6. This study demonstrates the sensitivity of adult mussel growth to subtle variation in environmental conditions occurring within and among lakes, with potential consequences for mussel population dynamics and community structure and function.     

Pollution characteristics and risk assessment of heavy metals in the soil of a construction waste landfill site

Heavy metals found in construction waste can enter soil and water bodies through surface runoff and leachate, where they represent an environmental hazard. In this study, we investigate the pollution characteristics and ecological risks of eight heavy metals (Cd, Cr, Cu, Mn, Ni, Pb, Zn, and As) in the soils of an unofficial construction waste landfill site in Beijing, China. The results indicate that long-term disposal of construction waste in the dry riverbed can reduce the pH value of the soil, increase the soil organic carbon content, and affect the total amount and distribution of heavy metals. Moreover, the landfill site pollutes the external soil environment, with Cd, Zn, Pb, and Cu as the characteristic pollutants. According to the Nemerow comprehensive pollution index and potential ecological risk assessment, heavy metal pollution decreases in the following order: internal soil > bottom soil > boundary soil. Cd, Zn, Pb, and Cu pollution is higher in the internal region, with single heavy-metal pollution indexes (Pi) of 1.41, 1.65, 1.26, and 1.28, respectively. Conversely, the Pi for Cr is higher in boundary and bottom soils (1.91 and 1.94, respectively). Risk assessment codes indicate that Cd and Mn pose the greatest environmental risk (31.9% and 17.8%, respectively) as they have the highest effective content, bioavailability, and mobility. Thus, environmental monitoring is a necessity for these metals.     

Use of a Sentinel System for Field Measurements of Cryptosporidium parvum Oocyst Inactivation in Soil and Animal Waste

A small-volume sentinel chamber was developed to assess the effects of environmental stresses on survival of sucrose-Percoll-purified Cryptosporidium parvum oocysts in soil and animal wastes. Chambers were tested for their ability to equilibrate with external chemical and moisture conditions. Sentinel oocysts were then exposed to stresses of the external environment that affected their viability (potential infectivity), as indicated by results of a dye permeability assay. Preliminary laboratory experiments indicated that temperatures between 35 and 50°C and decreases in soil water potential (−0.003 to −3.20 MPa) increased oocyst inactivation rates. The effects of two common animal waste management practices on oocyst survival were investigated on three dairy farms in Delaware County, N.Y., within the New York City watershed: (i) piling wastes from dairy youngstock (including neonatal calves) and (ii) spreading wastes as a soil amendment on an agricultural field. Sentinel containers filled with air-dried and sieved (2-mm mesh) youngstock waste or field soil were wetted and inoculated with 2 million oocysts in an aqueous suspension and then placed in waste piles on two different farms and in soil within a cropped field on one farm. Controls consisted of purified oocysts in either phosphate-buffered saline or distilled water contained in sealed microcentrifuge tubes. Two microdata loggers recorded the ambient temperature at each field site. Sentinel experiments were conducted during the fall and winter (1996 to 1997) and winter (1998). Sentinel containers and controls were removed at 2- to 4-week intervals, and oocysts were extracted and tested by the dye permeability assay. The proportions of potentially infective oocysts exposed to the soil and waste pile material decreased more rapidly than their counterpart controls exposed to buffer or water, indicating that factors other than temperature affected oocyst inactivation in the waste piles and soil. The effect of soil freeze-thaw cycles was evident in the large proportion of empty sentinel oocysts. The potentially infective sentinel oocysts were reduced to <1% while the proportions in controls did not decrease below 50% potentially infective during the first field experiment. Microscopic observations of empty oocyst fragments indicated that abrasive effects of soil particles were a factor in oocyst inactivation. A similar pattern was observed in a second field experiment at the same site.     

A hydrobiological survey of a polluted canal

The present state of a man-cut canal and a waste stream discharging into it was assessed. Some chemical and physical aspects of the study area have been measured and the diversity of the macroinvertebrates has been quantified.Species diversity of the net populations varied inversely to the degree of pollution. In the benthos, however, the nature of the bottom seemed to be largely responsible for the changes in community composition: the indices of diversity increased with increase in the amounts of silt and organic detritus. The ranges of phosphate, nitrite, ammonia, temperature, dissolved oxygen, chlorine (in chlorides), hardness, pH, transparency and velocity of the water were insufficient to produce detectable effects upon the diversity of the fauna.The waste stream had no macroscopic animal, save for the pollution-tolerant oligochaete, Limnodrilus.     

The effect of diapause emergence on the seasonal dynamics of a zooplankton assemblage

1. The role of seasonal phenology in the emergence of zooplankton from diapause in patterns of seasonal abundance in the water column was investigated in Oneida Lake, New York. Replicate emergence traps, placed in contact with the lake sediments at two locations (one at a shallow site and one at a deep site), were monitored between May and August.
2. Although six rotifer taxa showed a clear seasonal succession in the water column throughout the study period, all but one taxon emerged exclusively in spring. Three cladoceran and three calanoid copepod species, also present in the water column throughout the study period, again showed predominantly spring emergence. In contrast, three cyclopoid copepod species had distinct seasonal periods of emergence that corresponded, at least in part, to the timing of abundance peaks in the plankton.
3. These results for a single lake are largely consistent with patterns observed or inferred by other investigators for other lakes: variable dependence of abundance in the plankton on diapause emergence for species with long-lived diapausing eggs (i.e. rotifers, cladocerans and calanoid copepods), and much closer dependence for species with short-lived diapausing immature stages (i.e. cyclopoid copepods).     

Use of a sentinel system for field measurements of Cryptosporidium parvum oocyst inactivation in soil and animal waste

A small-volume sentinel chamber was developed to assess the effects of environmental stresses on survival of sucrose-Percoll-purified Cryptosporidium parvum oocysts in soil and animal wastes. Chambers were tested for their ability to equilibrate with external chemical and moisture conditions. Sentinel oocysts were then exposed to stresses of the external environment that affected their viability (potential infectivity), as indicated by results of a dye permeability assay. Preliminary laboratory experiments indicated that temperatures between 35 and 50 degrees C and decreases in soil water potential (-0.003 to -3.20 MPa) increased oocyst inactivation rates. The effects of two common animal waste management practices on oocyst survival were investigated on three dairy farms in Delaware County, N.Y., within the New York City watershed: (i) piling wastes from dairy youngstock (including neonatal calves) and (ii) spreading wastes as a soil amendment on an agricultural field. Sentinel containers filled with air-dried and sieved (2-mm mesh) youngstock waste or field soil were wetted and inoculated with 2 million oocysts in an aqueous suspension and then placed in waste piles on two different farms and in soil within a cropped field on one farm. Controls consisted of purified oocysts in either phosphate-buffered saline or distilled water contained in sealed microcentrifuge tubes. Two microdata loggers recorded the ambient temperature at each field site. Sentinel experiments were conducted during the fall and winter (1996 to 1997) and winter (1998). Sentinel containers and controls were removed at 2- to 4-week intervals, and oocysts were extracted and tested by the dye permeability assay. The proportions of potentially infective oocysts exposed to the soil and waste pile material decreased more rapidly than their counterpart controls exposed to buffer or water, indicating that factors other than temperature affected oocyst inactivation in the waste piles and soil. The effect of soil freeze-thaw cycles was evident in the large proportion of empty sentinel oocysts. The potentially infective sentinel oocysts were reduced to <1% while the proportions in controls did not decrease below 50% potentially infective during the first field experiment. Microscopic observations of empty oocyst fragments indicated that abrasive effects of soil particles were a factor in oocyst inactivation. A similar pattern was observed in a second field experiment at the same site.     

Persistence of a Salmonella enterica Serovar Typhimurium DT12 Clone in a Piggery and in Agricultural Soil Amended with Salmonella-Contaminated Slurry

Prevalence of Salmonella enterica on a Danish pig farm presenting recurrent infections was investigated. A comparison of the pulsed-field gel electrophoresis patterns of fecal isolates from piggeries, waste slurry, and agricultural soil amended with Salmonella-contaminated animal waste (slurry) and subclinical isolates from the same farm (collected in 1996 and later) showed identical patterns, indicating long-term persistence of the Salmonella enterica serovar Typhimurium DT12 clone in the herd environment. Furthermore, when Salmonella-contaminated slurry was disposed of on the agricultural soil (a common waste disposal practice), the pathogen was isolated up to 14 days after the spread, indicating potentially high risks of transmission of the pathogen in the environment, animals, and humans.     

Availability and utilization of waste fish feed by mussels Mytilus edulis in a commercial integrated multi-trophic aquaculture (IMTA) system: A multi-indicator assessment approach

Fish feed waste enhancement of the particulate food supply and performance of mussels Mytilus edulis suspended near salmon cages at an integrated multi-trophic aquaculture (IMTA) site was assessed using a multi-indicator approach. Dietary indicators included bulk measurements of seston quantity and nutritional quality, proximate analysis (PA), fatty acid (FA) and stable isotope (SI) composition. Mussel tissue indicators consisted of PA and FA composition. Mussel performance was assessed from physiological integrations (scope for growth, SFG), growth efficiency (K₂) and condition index (CI). All measurements were made over 2 days at a commercial IMTA farm and a monoculture mussel farm in the Bay of Fundy (Canada). Significant differences detected in seston quantity and quality were within the range of natural spatial variability. The SFG of IMTA mussels was lower (28.71 J h⁻¹) than monoculture mussels (38.71 J h⁻¹) and reflected site differences in natural food availability and composition that affected absorption rate. PA of mussel organs didn't reflect a significant fish feed contribution to the mussel diet. However, dietary enhancement and assimilation of fish feed waste was demonstrated by significantly higher levels of feed FA biomarkers 20:1ω9, 18:2ω6, 18:1ω9 and low ω3/ω6 ratio in seston, mussel tissues and feces at the IMTA site than at the mussel farm. SI (δ¹³C and δ¹⁵N) in seston and mussel feces significantly differed among sites and IMTA mussels had significantly higher CI (21%) than monoculture individuals (16%). It was concluded that bulk indicators of the diet, short-term physiological integrations, and PA of mussel tissues have a limited capacity to detect dietary enhancement at IMTA sites. FA and SI tracers of fish feed waste were shown to be more sensitive for detecting the low-levels of diet enhancement within the large range of natural seston variation.     

Cattle feed or bioenergy? Consequential life cycle assessment of biogas feedstock options on dairy farms

On‐farm anaerobic digestion (AD) of wastes and crops can potentially avoid greenhouse gas (GHG) emissions, but incurs extensive environmental effects via carbon and nitrogen cycles and substitution of multiple processes within and outside farm system boundaries. Farm models were combined with consequential life cycle assessment (CLCA) to assess plausible biogas and miscanthus heating pellet scenarios on dairy farms. On the large dairy farm, the introduction of slurry‐only AD led to reductions in global warming potential (GWP) and resource depletion burdens of 14% and 67%, respectively, but eutrophication and acidification burden increases of 9% and 10%, respectively, assuming open tank digestate storage. Marginal GWP burdens per Mg dry matter (DM) feedstock codigested with slurry ranged from –637 kg CO₂e for food waste to +509 kg CO₂e for maize. Codigestion of grass and maize led to increased imports of concentrate feed to the farm, negating the GWP benefits of grid electricity substitution. Attributing grass‐to‐arable land use change (LUC) to marginal wheat feed production led to net GWP burdens exceeding 900 kg CO₂e Mg^?1 maize DM codigested. Converting the medium‐sized dairy farm to a beef‐plus‐AD farm led to a minor reduction in GWP when grass‐to‐arable LUC was excluded, but a 38% GWP increase when such LUC was attributed to marginal maize and wheat feed required for intensive compensatory milk production. If marginal animal feed is derived from soybeans cultivated on recently converted cropland in South America, the net GWP burden increases to 4099 kg CO₂e Mg^?1 maize DM codigested – equivalent to 55 Mg CO₂e yr^?1 per hectare used for AD‐maize cultivation. We conclude that AD of slurry and food waste on dairy farms is an effective GHG mitigation option, but that the quantity of codigested crops should be strictly limited to avoid potentially large international carbon leakage via animal feed displacement.     

Water pollution by a land-based trout farm

In 1992, wastes from a land-based trout (Oncorhynchus mykiss) farm on a small stream in Brandenburg were investigated. This trout farm consists of 15 basins with a total volume of about 170 m³ using open water recirculation without water purification. The water supply from the stream is about 110 L/s and about 240 L/s are recycled by pumps. In 1991, the total production of rainbow trout was 20 t. Investigations included the discharge of nitrogen, phosphorus, COD and suspended matter resulting from the fish production, measured as the difference between inflow and outflow water. The average daily output was 466 g/t nitrogen, 157 g/t phosphorus, 3145 g/t COD and 30 L/t suspended dry matter. The feed conversion ratio was 1.33 kg/kg gain. These results indicated a reduction in waste discharge by about 53% for nitrogen and 42% for phosphorus compared to previous results in former Eastern Germany.     

Influence of inoculum activity on the bio-methanization of a kitchen waste under different waste/inoculum ratios

The use of a granular inoculum prevented acidification during the anaerobic batch biodegradation of a kitchen waste for waste/inoculum ratios in the range of 0.5–2.3 g VS/g VS, when the alkalinity/COD ratio was 37 mg NaHCO₃/g COD. In similar experiments but using a suspended sludge with a significantly lower activity, the methane production rates and the biodegradability were significantly lower and the pH decreased below 5.5 at the waste/inoculum ratio of 2.3 g VS/g VS. When the added alkalinity was decreased to 2 mg NaHCO₃/g COD, the ratio waste/inoculum was clearly more important than the inoculum activity, since, irrespective of the sludge used, acidification occurred at waste/inoculum ratios higher than 0.5 g VS/g VS. The advantage of using granular sludge was further investigated in order to define reasonable condition of waste/inoculum ratio and added alkalinity that could be applied in practice. For a waste/inoculum ratio of 1.35, there were no significant differences between the results obtained for the biodegradability and maximum methane production rate (MMPR), when the alkalinity decreased from 44 to 22 mg NaHCO₃/g COD.     

Persistence of a Salmonella enterica serovar typhimurium DT12 clone in a piggery and in agricultural soil amended with Salmonella-contaminated slurry

Prevalence of Salmonella enterica on a Danish pig farm presenting recurrent infections was investigated. A comparison of the pulsed-field gel electrophoresis patterns of fecal isolates from piggeries, waste slurry, and agricultural soil amended with Salmonella-contaminated animal waste (slurry) and subclinical isolates from the same farm (collected in 1996 and later) showed identical patterns, indicating long-term persistence of the Salmonella enterica serovar Typhimurium DT12 clone in the herd environment. Furthermore, when Salmonella-contaminated slurry was disposed of on the agricultural soil (a common waste disposal practice), the pathogen was isolated up to 14 days after the spread, indicating potentially high risks of transmission of the pathogen in the environment, animals, and humans.     

Perennial warm‐season grasses for producing biofuel and enhancing soil properties: an alternative to corn residue removal

Removal of corn (Zea mays L.) residues at high rates for biofuel and other off‐farm uses may negatively impact soil and the environment in the long term. Biomass removal from perennial warm‐season grasses (WSGs) grown in marginally productive lands could be an alternative to corn residue removal as biofuel feedstocks while controlling water and wind erosion, sequestering carbon (C), cycling water and nutrients, and enhancing other soil ecosystem services. We compared wind and water erosion potential, soil compaction, soil hydraulic properties, soil organic C (SOC), and soil fertility between biomass removal from WSGs and corn residue removal from rainfed no‐till continuous corn on a marginally productive site on a silty clay loam in eastern Nebraska after 2 and 3 years of management. The field‐scale treatments were as follows: (i) switchgrass (Panicum virgatum L.), (ii) big bluestem (Andropogon gerardii Vitman), and (iii) low‐diversity grass mixture [big bluestem, indiangrass (Sorghastrum nutans (L.) Nash), and sideoats grama (Bouteloua curtipendula (Michx.) Torr.)], and (iv) 50% corn residue removal with three replications. Across years, corn residue removal increased wind‐erodible fraction from 41% to 86% and reduced wet aggregate stability from 1.70 to 1.15 mm compared with WSGs in the upper 7.5 cm soil depth. Corn residue removal also reduced water retention by 15% between ?33 and ?300 kPa potentials and plant‐available water by 25% in the upper 7.5 cm soil depth. However, corn residue removal did not affect final water infiltration, SOC concentration, soil fertility, and other properties. Overall, corn residue removal increases erosion potential and reduces water retention shortly after removal, suggesting that biomass removal from perennial WSGs is a desirable alternative to corn residue removal for biofuel production and maintenance of soil ecosystem services.     

Growth, survival and fluctuating asymmetry of Iceland scallops in a test of density-dependent growth in a natural bed

We report an experiment designed to test for overpopulation in an Iceland scallop, Chlamys islandica (O.F. Müller), slow-growing bed. Scallops were installed in pearl nets at the site of the scallop bed and in a nearby unpopulated site, near the bottom and far from the bottom. With this set-up, all groups, except that one near the bottom inside the bed, were free from potential overpopulation effects. In addition, there were two stocking densities to test for containment effects.Shell growth was higher at 2.0 m above the bottom, outside the scallop bed, than at the three other site and height combinations, which were not significantly different from each other. There was a borderline effect of site on soft tissue growth, which was probably slower at the donor site. We conclude that there was no evidence of overpopulation in the scallop bed. On both sites, soft tissue growth was slowest near the bottom, irrespective of group size, intermediate at 2.0 m height, high population density, and fastest at 2.0 m height, low population density. Survivorship was lower near the bottom, but was independent of site and of group size. Available data showed no sustained vertical patterns in phytoplankton concentration in the water column. These results suggest that food depletion occurred in the pearl nets, but that density-independent factors dominated density-dependent factors in the pearl nets near the bottom. Likely explanations involve the interaction between containment effects and current speed variations in the benthic boundary layer. Survivorship decreased with fluctuating asymmetry of the ears of the shells. Fluctuating asymmetry, therefore, may provide a means of including individual effects in growth experiments and forecasting the ability of spat to resist density-independent mortality agents.     

Effect of the inclusion of food waste in pig diets on growth performance, carcass and meat quality

Food waste from fish and fruit shops was used as an alternative to the grain in grower-finisher pig diets. Two diets were formulated on an iso-nutrient basis (14 MJ digestible energy per kg, 160 g crude protein per kg on a dry-matter basis) to contain 0 g of food waste per kg in the control diet and 50 g of fish-shop waste per kg and 120 g of fruit-shop waste per kg in the experimental diet. In the study, 28 pigs per diet (seven pigs per pen) were fed ad libitum from 20 kg to 100 kg, then, they were slaughtered and the carcass characteristics determined. The inclusion of food waste in the diet had no significant effect (P>0.05) on average daily feed intake (2.12 v. 2.20 kg/day), average daily gain (0.74 v. 0.78 kg/day), or gain/feed (0.35 v. 0.35 kg per kg). In the case of the experimental diet, backfat thickness was significantly lower (18.0 v. 21.3 mm, P < 0.01). The results of the taste test indicated that the meat from food waste-fed pigs had acceptable organoleptic quality although a very light aroma to fish was observed in the bacon (P < 0.01).It was concluded that food waste from the fish and fruit shops could be included in grower-finisher pig diets without any detrimental effect on growth performance and only minor effects on carcass characteristics and meat quality.