Tail biting has several identified feeding-related risk factors. Tail biters are often said to be lighter and thinner than other pigs in the pen, possibly because of nutrition-related problems such as reduced feed intake or inability to use nutrients efficiently. This can lead to an increase in foraging behavior and tail biting. In this study, a total of 55 pigs of different ages were selected according to their tailbiting behavior (bouts/hour) and pen-feeding system to form eight experimental groups: tail-biting pigs (TB), victim pigs (V) and control pigs from a tail-biting pen (Ctb) and control pen (Cno) having either free access to feed with limited feeding space or meal feeding from a long trough. After euthanasia, a segment of jejunal cell wall was cut from 50 cm (S50) and 100 cm (S100) posterior to the bile duct. Villus height, crypt depth and villus : crypt ratio (V : C) were measured morphometrically. Blood serum concentration of minerals and plasma concentration of amino acids (AA) was determined. Villus height was greater in Cno than Ctb pigs in the proximal and mid-jejunum (P , 0.05), indicative of better ability to absorb nutrients, and increased with age in the proximal jejunum (P , 0.001). Serum mineral concentration of inorganic phosphate (P i ) and calcium (Ca) was lower in Ctb compared with Cno pigs, and that of P i in V compared with all the other pigs. Many non-essential AA were lower in pigs from tail-biting pens, and particularly in victim pigs. Free access feeding with shared feeding space was associated with lower levels of essential AA in blood than meal feeding with simultaneous feeding space. Our data suggest that being a pig in a tail-biting pen is associated with decreased jejunal villus height and blood AA levels, possibly because of depressed absorption capacity, feeding behavior or environmental stress associated with tail biting. Victim pigs had lower concentrations of AA and P i in plasma, possibly as a consequence of being bitten.
Digesta viscosity, ileal transit time of digesta, apparent ileal protein digestibility and apparent metabolisable energy (AME(N)) of diets based on wheat and dehulled barley (WB), oats (O) or a mixture of these (WBO) fed as such or with enzyme supplementation in three- and six-week old turkeys and broilers were investigated. In addition, differences between ileal digestibility and AME(N) calculated by using titanium dioxide (TiO2), chromic oxide (Cr2O3) or acid insoluble ash (AIA) as indigestible markers were compared. Digesta viscosities were generally moderate reaching from 2.5 mPa x s to 7.3 mPa x s. The highest viscosities were observed in WBO diets. Viscosities were reduced with age in broilers, and were generally higher in turkeys than in broilers, especially at six weeks of age. Digesta retention time in ileum was elongated with age of the birds, pronouncedly in broilers. Oat inclusion to the diets decreased retention time especially in broilers at six weeks of age. Apparent ileal digestibility of protein ranged from 0.64-0.83, was lower at six weeks of age than at three weeks of age and generally lowest in O diets, especially in turkeys. AME(N) of the diets ranged from 11.2-13.4 MJ/kg being higher at six weeks of age than at three weeks of age. AME(N) of Diets O was the lowest but AME(N) of WBO diets was higher than that of WB diets indicating a synergistic interaction of cereals, this trend being more pronounced in broilers. Enzyme supplementation decreased viscosity and improved AME(N) in most diets, but did not affect ileal protein digestibility. Differences between ileal digestibility estimates obtained with TiO2 or Cr2O3 were small and mainly not significantly different from 0. AME(N) estimates were generally higher when calculated with Cr2O3 than with TiO2. AIA gave remarkably lower AME(N) values than TiO2 (the significant differences ranging from 0.24-0.94 MJ/kg). In addition, effects of markers on AME(N) estimates interacted with age of the birds and dietary treatments.
Hännänpurenta on sikojen häiriökäyttäytymisen muoto, jonka tarkkaa alkuperää ei tunneta.Hännänpurennalle on kuitenkin löydetty laajoissa kartoituksissa lukuisia ympäristöperäisiäriskitekijöitä, jotka eivät kuitenkaan kaikilla yksilöillä johda hännänpurentakäyttäytymiseen.Yhteistä riskitekijöille on niiden aiheuttama stressi eläimelle. Sikayksilöt saattavat reagoidastressoreiden läsnäoloon yksilöllisesti, mikä selittäisi ilmiön, missä samassa ympäristössä yksisika puree ja toinen ei.Stressikäyttäytymistä voidaan tutkia vertaamalla stressiin liittyvien käyttäytymismuotojenesiintymistä ja aivoissa tapahtuvia neurobiologisia muutoksia ajallisesti ja määrällisesti.Serotoniini ja dopamiini ovat hermovälittäjäaineita, joilla on yhteys muun muassakäyttäytymiseen ja häiriökäyttäytymiseen. Kroonisen stressin tiedetään muuttavan aivojenrakennetta ja toimintaa.Tässä tutkimuksessa etsitään neurobiologisia ja fysiologisia eroja poikkeavasti janormaalisti käyttäytyvien sikayksilöiden välillä hännänpurennan aikana. Tutkittavat lihasiatjaettiin kolmeen ryhmään (PURIJA, UHRI, KONTROLLI) käyttäytymistarkkailun avulla saadunkeskimääräisen purentafrekvenssin mukaan. Ryhmiä verrataan anatomisten aivoalueiden(striatum, limbinen alue, etuaivokuori, hippokampus, talamus, hypotalamus) hermovälittäjäaineidenpitoisuuden ja niiden verenkierrossa olevien esiasteiden suhteen. Muita hännänpurentaan jastressiin liittyviä fysiologisia mekanismeja kartoitetaan määrittämällä kortisolin erityksenvuorokausirytmi syljestä, jejunumin alueen morfologinen suoliston kunto ja muu patologinen taihematologinen eroavuus ryhmien välillä. Tämä paperi keskittyy tutkimusten taustan jamenetelmien esittelyyn sekä koeryhmien identifiointiin. Fysiologisten näytteiden analysointi onyhä kesken.Tutkimus kuuluu yhteispohjoismaiseen NKJ- hankkeeseen “Tail biting and tail docking inthe pig: biological mechanisms, prevention, treatment and economic aspects”. Hankkeessaetsitään hännänpurentaan johtavia yksilöllisiä, ympäristö- ja rehuperäisiä riskitekijöitä, purentaaennaltaehkäiseviä ja purentaepidemian pysäyttäviä keinoja, toimivia hoidon- ja kivunlievityksenmuotoja ja mallitetaan hännänpurennan aiheuttamia taloudellisia kustannuksia.
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