Growth performance, carcass traits and meat quality of growing pigs on different feeding regimes slaughtered at 145\u2009kg BW

This study investigated the effects of feeding regime on growth performance, carcass traits and meat quality of pigs slaughtered at around 145 kg BW. A total of 96 barrows housed in eight pens were allotted to three groups in each pen. One group was fed ad libitum (AL) and the others were fed according to two quasi AL feeding regimes adjusting feed allowances with increasing BW. At slaughterhouse, the weights of the main lean and fat cuts were recorded, and a sample of longissimus lumborum (LL) was taken for physical and chemical analyses. Average daily gain (ADG) approached 940 g d1, and gain to feed ratio (G:F) was close to 0.38. Compared with the AL-feeding regime, the feed restriction reduced the pigs\u2019 ADG (3.5%), feed intake (7.4%) and carcass weight (3%) (p<0.01), but improved their G:F (\ufe4%, p<0.01). Feeding regime did not affect meat quality traits and exerted only minor effects on the weight of primal cuts and on the fatty acid composition of the intramuscular fat of the LL. However, AL-fed pigs tended to yield heavier fat cuts and showed a greater proportion of saturated fatty acid in the LL when compared to restricted feed barrows. In conclusion, moderate restriction in the feeding of medium\u2013heavy pigs seems advisable, as it improves feed efficiency and could cut feed costs compared with the AL-feeding regime without affecting carcass and meat characteristics

Effect of growth rate on live performance, carcass and green thigh traits of finishing Italian heavy pigs

This study aimed at investigating the effects of growth rate (GR) on live performance, carcass and dressed green ham (DRHAM) traits of finishing heavy pigs managed in accordance with the regulations governing the production of Protected Denomination of Origin (PDO) dry-cured hams. Data were obtained from 233 crossbred pigs restrictively fed from 90 to 165 kg BW. Individual BW, daily feed intake, and weights of carcass and main cuts were recorded. Thighs were measured for subcutaneous fat thickness, analysed for fatty acid composition of subcutaneous fat, and dry-cured hams were weighed. Records were classified according to GR quartile, calculated using the residuals of a statistical model that included the effects of pen, sex and diet. Data were analysed using the same model with the addition of the effect of GR quartile. Average GR ranged from 578 in the first quartile to 748 g/d in the fourth. Final BW and weights of carcass, DRHAM and dry-cured ham increased as the GR quartile increased (p < .01). An increase in GR improved feed efficiency linearly (p < .001) and tended to increase the thickness of subcutaneous fat of DRHAM, whereas seasoning losses decreased linearly with increasing average GR. In conclusion, targeting the GR of finishing pigs at a minimum of 750 g/d and consequently increasing final BW to around 175–180 kg may be a way to improve feed efficiency and some quality traits of DRHAM

The influence of feeding behaviour on growth performance, carcass and meat characteristics of growing pigs

This study investigated the effect of the feeding behaviour on growth performance, and car- cass and meat characteristics of 96 barrows fed ad libitum or restrictively with high or low amino acids (AA) diets according to a 2 7 2 factorial design. The feeding behaviour traits were measured with automated feeders. From 86 kg BW, half of the pigs were given feeds with high indispensable (AA) contents, while the other half received feeds with indispensable AA contents reduced by 9% in early finishing (86\u2013118 kg BW) and by 18% in late finishing (118\u2013145 kg BW). Body lipid and protein retentions were estimated from BW and backfat depth measures recorded at the beginning and end of each period. Pigs were slaughtered at 145 kg BW and carcass and meat quality data were recorded. Phenotypic correlations among feeding behaviours, growth performances, and carcass and meat traits were com- puted from all the data after adjustment for the effects of feeding treatments. As feeding rate was the behavioural trait most highly correlated with performance and carcass traits, the records of each pig were classified into feeding rate tertiles. Then, the data were statistically analysed using a mixed model, which included feed restriction (FR), AA reduction (AAR), the FR 7 AAR interaction and the feeding rate tertile as fixed factors, and pen as a random factor. Pigs eating faster (52.1 to 118.9 g/min) had significantly greater final body weights (16%), average daily weight gains (27%), estimated protein gains (22%), estimated lipid retention (46%), carcass weights (16%), weights of lean cuts (14%), weights of fat cuts (21%), proportions of fat in the carcass (14%), and 4% lower proportions of carcass lean cuts than pigs eating slowly (12.6 to 38.2 g/min). Manipulating the eating rate, through man- agement or genetic strategies, could affect feed intake and subsequent growth perfor- mance, hence carcass quality, but have little influence on feed efficiency

Sublethal Effects of Some Veterinary Antibacterials on Freshwater Organisms

The problem of the presence of pharmaceuticals in the environment and of their possible effects on ecosystems has been evidenced only in the last two decades, thanks to the progresses in analytical chemistry, and also to the progressive refinement of toxicological bioassays, leading to the detection of more subtle effects of pharmaceuticals on model organisms. In the last decade, progresses have been made also from the legislative point of view, introducing the duty of accurate evaluation of environmental impact for all newly commercialized drugs. Nevertheless, there is still a lack of knowledge about the environmental effects of pharmaceuticals. In the veterinary field, there are particular concerns about the environmental impact of livestock mass treatments (prophylactic/metaphylactic) which are administered for some days, at full dose and to a wide number of animals. Consequently, large quantities of active substances are released into the environment. Aim of this thesis, presented as a collection paper, was the evaluation of some sublethal effects of antibacterials, employed in mass treatments, on freshwater organisms. This in order to obtain a more in depth picture of the risks they could pose to the aquatic environment. The sensitivity of Daphnia curvirostris and Daphnia magna toward 10 antibacterials [enrofloxacin (EFX), ciprofloxacin(CPX), sulfaguanidine (SGD), sulfadiazine (SDZ), sulfamethazine (SMZ), sulfaquinoxaline (SQO), sulfaclozine (SCZ), sulfamerazine (SMA), sulfadimethoxine (SDM) and trimethoprim (TMP)] and some of their binary mixtures, was compared. Furthermore, a tentative prolonged-toxicity test (lasting 13 days) was settled up in order to evidence toxic responses with drug concentrations that were uneffective in the classic 48h immobilization test. Results showed that D.curvirostris was more sensitive than D.magna to the majority of compounds (7 out of 10). Lowest 48h EC50s were obtained with EFX (4.3 mg L-1 in D.curvirostris) and SGD (6.2 mg L-1 in D.magna). The toxicity of paired compounds was always additive or less than additive. In the prolonged-toxicity test mortality and/or reproduction inhibition were constantly observed. It was concluded that: (1) D.curvirostris could be a suitable model for the evaluation of acute toxicity of antibacterials; (2) the toxicity of EFX and SGD should be given special attention (3) the concentration addition is usually a reasonable worst case estimation of the environmental impact of antibacterial mixtures. Some veterinary antibacterials which may contaminate the aquatic environment due to their use in livestock and/or aquaculture mass treatments were evaluated for their effects on swimming activity in D.magna (primary consumer) and Poecilia reticulata (secondary consumer). Results showed that the chosen endpoint may call to the attention of ecotoxicology some compounds otherwise negligible, based on lethality test. Sublethal effects of TMP were then evaluated in four freshwater organisms: Pseudokirchneriella subcapitata and Lemna minor (growth inhibition), D.magna (reproduction and growth inhibition) and P.reticulata (swimming activity inhibition). TMP showed varying levels of toxicity in the four test performed, with NOEC for the various endpoints in the range of 3.12 to 25 mg L-1. The compound was active on P. reticulata at concentration ≥50 mg L-1 causing inhibition of swimming activity. L. minor was more sensitive than unicellular algae to TMP, with a NOEC of 12.5 mg L-1. The lowest NOEC (3.12 mg L-1) was obtained in D. magna reproduction test and then a Risk Quotient of <0.03 was calculated by comparing the PNEC (31.2 μg L-1) and the TMP concentrations usually detected in freshwater (<1 μg L-1). It was concluded that while TMP concentrations normally detected in surface water are below those able to evoke appreciable biological effects in the various aquatic organisms, TMP concentrations in aquaculture and hospital effluents can be one to three orders of magnitude higher. Furthermore, the co-occurrence and additive effects of other antifolic agents should be taken into account for a cautious risk assessment of the drug. 2 Multigenerational tests on D.magna were performed exposing two subsequent generation of the crustacean to EFX, his metabolite CPX and TMP. In F1 with respect to F0, both for growth and reproduction, a worsening trend of the response with EFX, a similar response with CPX and an attenuating trend with TMP was observed. Furthermore, the lowest EC20 for reproduction inhibition (1.27 mg L-1) was calculated for F1 exposed to EFX. However, other experimentations, longer and more complex, are necessary in order to confirm that EFX is more hazardous to daphnids than CPX and TMP. EC50s measured for the three assayed antibacterials were in the 6.49-36.53 mg L-1 range and therefore environmental unrealistic, except in case of exceptional contaminations that may occur in relation to poorly controlled wastewaters from pharmaceutical factories or excessive use of prophylactic treatments in aquacultureLa presenza di molecole farmacologicamente attive nell’ambiente è un problema che è stato sollevato solamente negli ultimi due decenni grazie, da un lato, all’affinamento delle tecniche analitiche e, dall’atro, alla messa a punto di bioassay sempre più sensibili. Nell’ultimo decennio inoltre, sono stati fatti notevoli passi avanti anche dal punto di vista normativo introducendo l’obbligo di un’accurata valutazione dell’impatto ambientale per tutti i nuovi principi attivi immessi in commercio. Tuttavia le conoscenze relative agli effetti dei farmaci nell’ambiente sono ancora piuttosto limitate. In campo veterinario particolare preoccupazione in relazione alla sicurezza ambientale destano i trattamenti di massa che vengono effettuati a scopo profilattico/metafilattico coinvolgendo un gran numero di animali che vengono trattati a dose piena per alcuni giorni con conseguente notevole rilascio di principi attivi nel suolo o nelle acque. Lo scopo di questa tesi, presentata sottoforma di collection paper, è stato quello di indagare alcuni effetti subletali di antibatterici, impiegati nei trattamenti di massa, su organismi acquatici, al fine di giungere ad una valutazione più accurata dei rischi che questi contaminanti possono comportare per il comparto dulciacquicolo. La sensibilità di Daphnia curvirostris e Daphnia magna è stata confrontata attraverso l’impiego di 10 antibatterici [enrofloxacina (EFX), ciprofloxacina (CPX), sulfaguanidina (SGD), sulfadiazina (SDZ), sulfametazina (SMZ), sulfachinossalina (SQO), sulfaclozina (SCZ), sulfamerazina (SMA), sulfadimetossina (SDM) e trimetoprim (TMP)] e di alcune loro miscele binarie. Inoltre, è stato condotto un test preliminare di tossicità prolungata (della durata di 13 gg), al fine di evidenziare effetti a concentrazioni che non avevano prodotto risposte a 48h col classico test di immobilizzazione. I risultati hanno permesso di osservare che D.curvirostris è più sensibile di D.magna alla maggior parte dei composti (7 su 10). Le più basse EC50 sono state ottenute con EFX (4.3 mg L-1 in D.curvirostris) e SGD (6.2 mg L-1 in D.magna). La tossicità delle miscele binarie è stata sempre additiva o sub additiva e i test prolungati hanno permesso di osservare in tutti i casi mortalità e/o inibizione della riproduzione. Si è concluso che: (1) D.curvirostris può essere un modello adatto per la valutazione della tossicità degli antibatterici; (2) particolare attenzione dovrebbe essere prestata alla tossicità di EFX e SGD; (3) generalmente il concetto di semplice additività è una stima cautelativa dell’impatto ambientale delle miscele di antibatterici. Sono stati valutati gli effetti di alcuni antibatterici sull’attività natatoria di D.magna e Poecilia reticulata. I risultati hanno permesso di osservare che l’end-point selezionato, a differenza dei test di letalità, consente di richiamare l’attenzione sulla tossicità ambientale di alcuni composti. Alcuni effetti subletali del TMP sono stati misurati in quattro organismi d’acqua dolce: Pseudokirchneriella subcapitata and Lemna minor (inibizione dell’accrescimento), D.magna (inibizione della riproduzione e della crescita) e P.reticulata (inibizione dell’attività natatoria). Il TMP ha mostrato diversi livelli di tossicità nei diversi organismi con NOEC che variavano da 3,12 a 25 mg L-1. Il composto era attivo su P.reticulata alla concentrazione ≥50 mg L-1 provocando un’inibizione dell’attività natatoria. La NOEC più bassa (3,12 mg L-1) è stata ottenuta nel test d’inibizione della riproduzione con D. magna, quindi, il confronto tra la PNEC (31,2 μg L) e le concentrazioni normalmente ritrovate nelle acque dolci (<1 μg L-1) ha permesso di calcolare un quoziente di rischio <0,03. Si è concluso che mentre le concentrazioni di TMP normalmente rilevate nelle acque superficiali non sarebbero in grado di provocare effetti biologici apprezzabili nei vari organismi acquatici, le concentrazioni di TMP impiegate in acquacoltura e ritrovate negli scarichi ospedalieri possono raggiungere livelli sino a tre ordini di grandezza superiori. Inoltre per un’analisi del rischio sufficientemente cautelativa la copresenza di TMP ed altri antifolici ed i possibili, conseguenti, effetti additivi dovrebbero essere tenuti in considerazione. Test multi generazionali sono stati effettuati su D.magna esponendo due generazioni consecutive a EFX, al suo metabolita CPX ed a TMP. In F1 rispetto ad F0 è stato osservato, sia sull’accrescimento che sulla riproduzione: un peggioramento degli effetti con EFX, risposte simili 4 con CPX, un’attenuazione degli effetti con TMP. Inoltre, l’ EC20 più bassa, relativa all’inibizione della riproduzione, è stata determinata per gli F1 esposti a EFX; tuttavia, disegni sperimentali più lunghi e complessi si rendono necessari al fine di confermare la maggior pericolosità, per i daphnidi, di EFX rispetto a CPX e TMP. Le EC50 misurate nei tre test variavano da 6,49 a 36,53 mg L-1 e sono, dunque, da considerarsi irrealistiche dal punto di vista ambientale salvo casi eccezionali di contaminazione che si possono verificare in occasione di scarso controllo dei reflui provenienti da stabilimenti farmaceutici o in relazione all’abuso di trattamenti profilattici in acquacoltur

Sublethal Effects of Some Veterinary Antibacterials on Freshwater Organisms

The problem of the presence of pharmaceuticals in the environment and of their possible effects on ecosystems has been evidenced only in the last two decades, thanks to the progresses in analytical chemistry, and also to the progressive refinement of toxicological bioassays, leading to the detection of more subtle effects of pharmaceuticals on model organisms. In the last decade, progresses have been made also from the legislative point of view, introducing the duty of accurate evaluation of environmental impact for all newly commercialized drugs. Nevertheless, there is still a lack of knowledge about the environmental effects of pharmaceuticals. In the veterinary field, there are particular concerns about the environmental impact of livestock mass treatments (prophylactic/metaphylactic) which are administered for some days, at full dose and to a wide number of animals. Consequently, large quantities of active substances are released into the environment. Aim of this thesis, presented as a collection paper, was the evaluation of some sublethal effects of antibacterials, employed in mass treatments, on freshwater organisms. This in order to obtain a more in depth picture of the risks they could pose to the aquatic environment. The sensitivity of Daphnia curvirostris and Daphnia magna toward 10 antibacterials [enrofloxacin (EFX), ciprofloxacin(CPX), sulfaguanidine (SGD), sulfadiazine (SDZ), sulfamethazine (SMZ), sulfaquinoxaline (SQO), sulfaclozine (SCZ), sulfamerazine (SMA), sulfadimethoxine (SDM) and trimethoprim (TMP)] and some of their binary mixtures, was compared. Furthermore, a tentative prolonged-toxicity test (lasting 13 days) was settled up in order to evidence toxic responses with drug concentrations that were uneffective in the classic 48h immobilization test. Results showed that D.curvirostris was more sensitive than D.magna to the majority of compounds (7 out of 10). Lowest 48h EC50s were obtained with EFX (4.3 mg L-1 in D.curvirostris) and SGD (6.2 mg L-1 in D.magna). The toxicity of paired compounds was always additive or less than additive. In the prolonged-toxicity test mortality and/or reproduction inhibition were constantly observed. It was concluded that: (1) D.curvirostris could be a suitable model for the evaluation of acute toxicity of antibacterials; (2) the toxicity of EFX and SGD should be given special attention (3) the concentration addition is usually a reasonable worst case estimation of the environmental impact of antibacterial mixtures. Some veterinary antibacterials which may contaminate the aquatic environment due to their use in livestock and/or aquaculture mass treatments were evaluated for their effects on swimming activity in D.magna (primary consumer) and Poecilia reticulata (secondary consumer). Results showed that the chosen endpoint may call to the attention of ecotoxicology some compounds otherwise negligible, based on lethality test. Sublethal effects of TMP were then evaluated in four freshwater organisms: Pseudokirchneriella subcapitata and Lemna minor (growth inhibition), D.magna (reproduction and growth inhibition) and P.reticulata (swimming activity inhibition). TMP showed varying levels of toxicity in the four test performed, with NOEC for the various endpoints in the range of 3.12 to 25 mg L-1. The compound was active on P. reticulata at concentration ≥50 mg L-1 causing inhibition of swimming activity. L. minor was more sensitive than unicellular algae to TMP, with a NOEC of 12.5 mg L-1. The lowest NOEC (3.12 mg L-1) was obtained in D. magna reproduction test and then a Risk Quotient of <0.03 was calculated by comparing the PNEC (31.2 μg L-1) and the TMP concentrations usually detected in freshwater (<1 μg L-1). It was concluded that while TMP concentrations normally detected in surface water are below those able to evoke appreciable biological effects in the various aquatic organisms, TMP concentrations in aquaculture and hospital effluents can be one to three orders of magnitude higher. Furthermore, the co-occurrence and additive effects of other antifolic agents should be taken into account for a cautious risk assessment of the drug. 2 Multigenerational tests on D.magna were performed exposing two subsequent generation of the crustacean to EFX, his metabolite CPX and TMP. In F1 with respect to F0, both for growth and reproduction, a worsening trend of the response with EFX, a similar response with CPX and an attenuating trend with TMP was observed. Furthermore, the lowest EC20 for reproduction inhibition (1.27 mg L-1) was calculated for F1 exposed to EFX. However, other experimentations, longer and more complex, are necessary in order to confirm that EFX is more hazardous to daphnids than CPX and TMP. EC50s measured for the three assayed antibacterials were in the 6.49-36.53 mg L-1 range and therefore environmental unrealistic, except in case of exceptional contaminations that may occur in relation to poorly controlled wastewaters from pharmaceutical factories or excessive use of prophylactic treatments in aquacultureLa presenza di molecole farmacologicamente attive nell’ambiente è un problema che è stato sollevato solamente negli ultimi due decenni grazie, da un lato, all’affinamento delle tecniche analitiche e, dall’atro, alla messa a punto di bioassay sempre più sensibili. Nell’ultimo decennio inoltre, sono stati fatti notevoli passi avanti anche dal punto di vista normativo introducendo l’obbligo di un’accurata valutazione dell’impatto ambientale per tutti i nuovi principi attivi immessi in commercio. Tuttavia le conoscenze relative agli effetti dei farmaci nell’ambiente sono ancora piuttosto limitate. In campo veterinario particolare preoccupazione in relazione alla sicurezza ambientale destano i trattamenti di massa che vengono effettuati a scopo profilattico/metafilattico coinvolgendo un gran numero di animali che vengono trattati a dose piena per alcuni giorni con conseguente notevole rilascio di principi attivi nel suolo o nelle acque. Lo scopo di questa tesi, presentata sottoforma di collection paper, è stato quello di indagare alcuni effetti subletali di antibatterici, impiegati nei trattamenti di massa, su organismi acquatici, al fine di giungere ad una valutazione più accurata dei rischi che questi contaminanti possono comportare per il comparto dulciacquicolo. La sensibilità di Daphnia curvirostris e Daphnia magna è stata confrontata attraverso l’impiego di 10 antibatterici [enrofloxacina (EFX), ciprofloxacina (CPX), sulfaguanidina (SGD), sulfadiazina (SDZ), sulfametazina (SMZ), sulfachinossalina (SQO), sulfaclozina (SCZ), sulfamerazina (SMA), sulfadimetossina (SDM) e trimetoprim (TMP)] e di alcune loro miscele binarie. Inoltre, è stato condotto un test preliminare di tossicità prolungata (della durata di 13 gg), al fine di evidenziare effetti a concentrazioni che non avevano prodotto risposte a 48h col classico test di immobilizzazione. I risultati hanno permesso di osservare che D.curvirostris è più sensibile di D.magna alla maggior parte dei composti (7 su 10). Le più basse EC50 sono state ottenute con EFX (4.3 mg L-1 in D.curvirostris) e SGD (6.2 mg L-1 in D.magna). La tossicità delle miscele binarie è stata sempre additiva o sub additiva e i test prolungati hanno permesso di osservare in tutti i casi mortalità e/o inibizione della riproduzione. Si è concluso che: (1) D.curvirostris può essere un modello adatto per la valutazione della tossicità degli antibatterici; (2) particolare attenzione dovrebbe essere prestata alla tossicità di EFX e SGD; (3) generalmente il concetto di semplice additività è una stima cautelativa dell’impatto ambientale delle miscele di antibatterici. Sono stati valutati gli effetti di alcuni antibatterici sull’attività natatoria di D.magna e Poecilia reticulata. I risultati hanno permesso di osservare che l’end-point selezionato, a differenza dei test di letalità, consente di richiamare l’attenzione sulla tossicità ambientale di alcuni composti. Alcuni effetti subletali del TMP sono stati misurati in quattro organismi d’acqua dolce: Pseudokirchneriella subcapitata and Lemna minor (inibizione dell’accrescimento), D.magna (inibizione della riproduzione e della crescita) e P.reticulata (inibizione dell’attività natatoria). Il TMP ha mostrato diversi livelli di tossicità nei diversi organismi con NOEC che variavano da 3,12 a 25 mg L-1. Il composto era attivo su P.reticulata alla concentrazione ≥50 mg L-1 provocando un’inibizione dell’attività natatoria. La NOEC più bassa (3,12 mg L-1) è stata ottenuta nel test d’inibizione della riproduzione con D. magna, quindi, il confronto tra la PNEC (31,2 μg L) e le concentrazioni normalmente ritrovate nelle acque dolci (<1 μg L-1) ha permesso di calcolare un quoziente di rischio <0,03. Si è concluso che mentre le concentrazioni di TMP normalmente rilevate nelle acque superficiali non sarebbero in grado di provocare effetti biologici apprezzabili nei vari organismi acquatici, le concentrazioni di TMP impiegate in acquacoltura e ritrovate negli scarichi ospedalieri possono raggiungere livelli sino a tre ordini di grandezza superiori. Inoltre per un’analisi del rischio sufficientemente cautelativa la copresenza di TMP ed altri antifolici ed i possibili, conseguenti, effetti additivi dovrebbero essere tenuti in considerazione. Test multi generazionali sono stati effettuati su D.magna esponendo due generazioni consecutive a EFX, al suo metabolita CPX ed a TMP. In F1 rispetto ad F0 è stato osservato, sia sull’accrescimento che sulla riproduzione: un peggioramento degli effetti con EFX, risposte simili 4 con CPX, un’attenuazione degli effetti con TMP. Inoltre, l’ EC20 più bassa, relativa all’inibizione della riproduzione, è stata determinata per gli F1 esposti a EFX; tuttavia, disegni sperimentali più lunghi e complessi si rendono necessari al fine di confermare la maggior pericolosità, per i daphnidi, di EFX rispetto a CPX e TMP. Le EC50 misurate nei tre test variavano da 6,49 a 36,53 mg L-1 e sono, dunque, da considerarsi irrealistiche dal punto di vista ambientale salvo casi eccezionali di contaminazione che si possono verificare in occasione di scarso controllo dei reflui provenienti da stabilimenti farmaceutici o in relazione all’abuso di trattamenti profilattici in acquacoltur

The sensitivity of Daphnia magna and Daphnia curvirostris to 10 antibacterials and to some of their binary mixtures: a comparison

Daphnia magna is a freshwater cladoceran largely employed in ecotoxicity tests due to its high sensitivity to xenobiotics, relative easiness of culturing, short parthenogenetic cycle and small dimensions. However, various studies have shown that other daphnids may be more sensitive than D.magna to some environmental contaminants. The use of indigenous species in toxicity tests has the advantage of generating ecologically relevant and environmentally realistic data for use in water quality guidelines. Aim of this study was to evaluate the suitability of Daphnia curvirostris for the acute toxicity test usually performed on D.magna, and to compare the sensitivity of the two species toward 10 antibacterials and to some of their binary mixtures. The D. curvirostris clone used in the tests was generated from a specimen collected in Rosolina (RO, coordinate WGS84: 45,138666698153 lat 12,3240131618937 lon), while D. magna was originally obtained from Ecotox LDS S.r.l. (Milano, Italy). Tests were conducted in accordance with the OECD 202 guideline . Daphnids were exposed to scaled concentrations of the following antibacterials: enrofloxacin (EFX), ciprofloxacin(CPX), sulfaguanidine (SGD), sulfadiazine (SDZ), sulfamethazine (SMZ), sulfaquinoxaline (SQO), sulfaclozine (SCZ), sulfamerazine (SMA), sulfadimetoxine (SDM) and trimethoprim (TMP). Furthermore, the toxicity of 4 mixtures was evaluated (TMP+SDZ, TMP+SDM, TMP+SQO and EFX+CPX). The calculated EC50s spanned three orders of magnitude, varying from 4.33 mg L-1 (EFX) to 421,1 mg L-1 (SDM) in D.curvirostris and from 5.21 mg L-1 (SGD) to 379.8 mg L-1 (SCZ) in D.magna. D.curvirostris showed to be more sensitive than D. magna to the assayed compounds, with the exception of SMA, SDZ and SDM. With binary mixtures simple additivity was mainly recorded. It was concluded that D.curvirostris is well suitable for the acute immobilisation test, and that its sensitivity to xenobiotics may often be greater than that of D.magna, probably due to its higher surface/volume quotient; besides, being naturally present in the water ponds of northern Italy, D.curvirostris can give a realistic picture of the local environmental impact of xenobiotics. Tests with D.curvirostris were also useful in confirming that, as already observed in previous experiments with D.magna, binary mixtures of antibacterials usually act in accordance to the expectable and reassuring criterion of simple addition

The sensitivity of Daphnia magna and Daphnia curvirostris to 10 veterinary antibacterials and to some of their binary mixtures

Aim of this study was to evaluate the suitability of Daphnia curvirostris for the acute toxicity test usually performed on Daphnia magna, and to compare the sensitivity of the two species toward 10 antibacterials [enrofloxacin (EFX), ciprofloxacin(CPX), sulfaguanidine (SGD), sulfadiazine (SDZ), sulfamethazine (SMZ), sulfaquinoxaline (SQO), sulfaclozine (SCZ), sulfamerazine (SMA), sulfadimethoxine (SDM) and trimethoprim (TMP)] and some of their binary mixtures. Furthermore, a tentative prolonged-toxicity test (lasting 13 d) was settled up in order to evidence toxic responses with drug concentrations that were uneffective in the classic 48 h immobilization test. Results showed that D. curvirostris was more sensitive than D. magna to the majority of compounds (6 out of 10). Lowest 48 h EC50s were obtained with EFX (4.3 mg L1 in D. curvirostris) and SGD (6.2 mg L1 in D. magna). The toxicity of paired compounds was always concentration- additive or less than concentration-additive. In the prolonged-toxicity test mortality and/or reproduction inhibition were constantly observed. It was concluded that: (1) D. curvirostris could be a suitable model for the evaluation of acute toxicity of antibacterials since its sensitivity was generally greater than that of D. magna; (2) the toxicity of EFX and SGD should be given special attention as the two compounds, in the prolonged test, showed to be active at concentrations of 0.9 mg L1 and 2.5 mg L1, respectively; (3) the concentration addition is usually a reasonable worst case estimation of the environmental impact of antibacterial mixtures

Growth and carcass traits of 145 kg body weight pigs fed according to different feeding regimes

This study aimed to investigate the effect of feeding regimen on growth and carcass traits and estimated energy balance of pigs slaughtered around 145 kg body weight (BW) and addressed to high quality baked ham production. At the beginning of the trial, 96 crossbred barrows (Topigs Talent) averaging 30.4\ub14.1 kg BW were randomly allotted into 8 pens (12 pigs per pen) equipped with electronic feeding stations. All animals were provided with the same feeds containing on average 13.6 ME MJ/kg and 161 g CP/kg as-fed. Within each pen, 4 pigs were assigned to an ad libitum (AL), 4 pigs to a low-high restricted and 4 pigs to a high-low restricted feeding regime. Individual feed intake was recorded daily, pigs were weighed weekly, and backfat depth (P2) was measured with an ultrasound device every 3 weeks, till the end of the experiment, when the pigs averaged 142.6\ub17.8 kg BW. Measurements of BW and P2 were used to estimate changes of body composition over the time, from which ME requirements for protein and lipid growth were derived. Estimated ME for growth and the measured ME intake were used to estimate the ME used for maintenance. All pigs were slaughtered in the same day in a commercial abattoir, and carcass and major cuts weights were recorded. Samples of Longissimus Dorsi were collected for physical and chemical analysis. After 24 h of chilling thighs were deboned and weighed. Traits were analysed according to a mixed model which accounted for the effects of pen (random) and of feeding regime. Pigs fed AL showed (P<0.01) higher growth rate and final BW (966 vs. 832 g/d, and 145 vs. 141 kg, respectively), lower gain:feed and higher estimated amount of ME for maintenance than restricted fed pigs (0.368 vs. 0.383, and 0.98 vs. 0.89 MJ/kg BW0.60, respectively), whereas carcass and meat quality traits were similar among feeding regimes. Pigs fed different restricted feeding regimes gave similar growth and carcass performances. In conclusion, the AL feeding regime allowed to attain the target 145 BW some days earlier than restricted feeding regimes, but growth rate was not greater enough to compensate increased feed intake, thus penalising feed efficiency of AL fed pigs

Effects of Veterinary Drugs on Swimming Activity in Two Freshwater Organisms.

Alterations in swimming activity may influence ecologically relevant performance, such as predation avoidance, prey capture, growth, stress resistance, mating, and longevity. The evaluation of swimming activity supports toxicological investigation with endpoints other than traditional LC50s values and may aid in investigating the environmental relevance of low-level exposures and determining \u201cno observable effect concentration\u201d (NOEC) and \u201clowest observable effect concentration\u201d (LOEC). In this chapter, some veterinary antibacterial compounds that may contaminate the aquatic environment due to their use in livestock and/or mass aquaculture treatments are evaluated for their effects on swimming activity of Daphnia magna (primary consumer) and Poecilia reticulata (secondary consumer). Results show that the chosen endpoint may call to the attention of ecotoxicology some compounds that are otherwise negligible, based on lethality tests

EFFETTI TOSSICI DELL\u2019ENROFLOXACINA SU DAPHNIA MAGNA, STUDIO CON DUE GENERAZIONI

The effects of enrofloxacin (EFX) on reproduction, survival and growth were evaluated in a two-generations study on Daphnia magna. In F0, lethality (EC50 9.78 mg L-1), even if less sensitive than the reproduction inhibition endpoint (EC50 6.49 mg L-1), was prevalent at high concentrations, preventing observation of the reproduction-inhibition plateau. Lowest LOEC for reproduction inhibition (3.13 mg L-1) was obtained in re-exposed F1. However, effects on reproduction (LOEC 6.25 mg L-1) were also observed in non-exposed F1 born to exposed F0, highlighting the reverberation of toxic effects of EFX along D. magna generations. Thus, It was concluded that multigenerational studies may detect otherwise unnoticed effects that could be relevant for the environmental equilibrium