Colon and fusus coli: anatomy and r

Colon and fusus coli: anatomy and regulatory physiology
The colon of the rabbit is divisible into a number of different positional
and morphologic parts. The ascending colon is very long, and divided into
148 R. Rees Davies, J.A.E. Rees Davies / Vet Clin Exot Anim 6 (2003) 139–153
five limbs extending forwards and back separated by flexures. The first limb
has three taeniae forming three rows of sacculations referred to as ‘‘haustrae.’’
In the second and third limbs the taeniae combine to a single taenia
and one row of haustra. The remainder of the ascending colon has no taeniae,
and lies coiled in the dorsal part of the abdominal cavity. Fecal pellets
can first be distinguished towards the end of the ascending colon. The transverse
colon is short, and ends in a muscular thickening known as the ‘‘fusus
coli,’’ a structure unique to lagomorphs. The separation of the colon into
two anatomical and physiologic parts by the fusus coli has led to a renaming
of these as ‘‘proximal’’ and ‘‘distal’’ colon, rather than using the more traditional
ascending/transverse/descending nomenclature. The fusus coli is a differential
pacemaker for the initiation of peristaltic waves in both proximal
and distal colon, and regulates the separation (by contractions of the taeniae/haustrae)
of fermentable material from indigestible fiber [35]. Researchers
have shown correlations between fusus coli activity and several potential
regulatory mechanisms, including autonomic nervous influences and circulating
levels of prostaglandins, aldosterone, and other substances. Aldosterone
levels are highest during hard feces production. However, it is not clear
whether this is cause or effect of the fusus coli activity. Prostaglandins have
been shown to inhibit the motility of the proximal colon and stimulate the
activity in the distal colon, aiding the production of caecotrophs [36]. The
involvement of the autonomic nervous system and adrenal glands in the regulation
of the fusus may be the reason (rather than immunosuppression)
why rabbits are prone to stress related gastrointestinal disease. After the
fusus coli, the descending colon and rectum return to simple tubular form
with thicker walls.
Food intake and cecotrophy: temporal relativity
Cecotrophs are pellets produced at the anus from the partially fermented
matter of the cecum rather than from unwanted fiber. Because they are not
waste material, they are not, strictly speaking, feces, although the term ‘‘soft
feces’’ is used synonymously with ‘‘cecotroph.’’ The process of cecotroph
ingestion is erroneously referred to as coprophagy. The cecotrophs are
ingested by the rabbit directly from the rectum as a result of a neurologic
licking response, and are swallowed whole without being chewed. Cecotrophy
is influenced by light, ingestive patterns, and varies between captive and
wild rabbits [37,38]. In wild rabbits most of the cecotrophy occurs during
daytime when rabbits are within their burrows. This is in contrast to the situation
in captive rabbits, where most of the cecotroph ingestion occurs at
night although it can occur at any time of the day or night [17]. Feed intake
patterns inversely follow cecotroph production—when cecotrophy is taking
place, food ingestion ceases. This is not a relationship that can be explained
by compensatory gastric fill or behavioral satisfaction, as applying collars
R. Rees Davies, J.A.E. Rees Davies / Vet Clin Exot Anim 6 (2003) 139–153 149
(preventing the rabbits from ingesting their cecotrophs) does not alter the
cecotroph production or the food ingestion patterns [37].
Hunger is stimulated by a number of factors including a dry mouth and
decreased blood levels of metabolites such as glucose, amino acids, and volatile
fatty acids [12]. Cecotrophy usually follows about 4 hours after ingestion
of food. Caged rabbits on a normal daylight pattern and fed ad libitum
show an increase in food intake from 3:00 to 5:00 PM, and food intake
remains high until midnight. There is then a decreased food intake until
2:00 AM, followed by a further increase peaking at 0:600 AM and ending at
0800 AM [4,19]. Cecotrophy therefore occurs mainly in the periods between
midnight and 02:00 AM, and again at 08:00 AM. When rabbits are fed a
restricted feeding regime rather than ad libitum, cecotroph production is
related to time of food ingestion and loses its influence from light signals
[37]. The degree of cecotroph ingestion is directly related to the fiber content
of the ingested foods. Cecotroph ingestion is highest when rabbits are fed on
a diet high in nondigestible fiber. Dietary fiber is distributed at a set ratio
between hard feces and cecotrophs. Cecotrophs have around 50% of the
crude fiber level of the ‘‘hard feces.’’ This is regardless of the level of fiber
in the food material. However, if dietary protein is restricted, the protein
level in the hard feces drops whilst that in the cecotrophs is conserved [8].

Resultados (español) 1:

Colon y fusus coli: Anatomía y fisiología reguladoraEl colon del conejo es divisible en un número de diferente posicióny las partes morfológicas. El colon ascendente es muy largo y se divide en148 r. Rees Davies, J.A.E. Rees Davies / Vet Clin Exot Anim 6 (2003) 139-153cinco miembros que se extiende adelante y atrás separados por flexiones. La primera partetiene tres tenias forma tres filas de sacculations contempladas como '' haustrae.''En el segundo y terceros miembros las tenias combinan para una sola teniay una fila de haustra. El resto del colon ascendente no tiene tenias,y se encuentra enrollado en la parte dorsal de la cavidad abdominal. Pellets fecalesen primer lugar se puede diferenciar hacia el final de los dos puntos ascendentes. La transversalcolon es corto y termina en un engrosamiento muscular conocido como el '' Osmancoli,'' una estructura única en lagomorfos. La separación de los dos puntos endos partes anatómicas y fisiológicas por el fusus coli ha conducido a un cambio de nombrede éstos como '' próxima '' y '' distal'' dos puntos, en lugar de utilizar el más tradicionalnomenclatura de ascendente y transversal/descendente. El fusus coli es un diferencialmarcapasos para el inicio de ondas peristálticas en tanto proximaly el colon distal y regula la separación (por contracciones de la tenias/haustrae)de material fermentable de fibra indigesta [35]. Investigadoreshan mostrado correlaciones entre fusus coli actividad y potencial de variosregulatory mechanisms, including autonomic nervous influences and circulatinglevels of prostaglandins, aldosterone, and other substances. Aldosteronelevels are highest during hard feces production. However, it is not clearwhether this is cause or effect of the fusus coli activity. Prostaglandins havebeen shown to inhibit the motility of the proximal colon and stimulate theactivity in the distal colon, aiding the production of caecotrophs [36]. Theinvolvement of the autonomic nervous system and adrenal glands in the regulationof the fusus may be the reason (rather than immunosuppression)why rabbits are prone to stress related gastrointestinal disease. After thefusus coli, the descending colon and rectum return to simple tubular formwith thicker walls.Food intake and cecotrophy: temporal relativityCecotrophs are pellets produced at the anus from the partially fermentedmatter of the cecum rather than from unwanted fiber. Because they are notwaste material, they are not, strictly speaking, feces, although the term ‘‘softfeces’’ is used synonymously with ‘‘cecotroph.’’ The process of cecotrophingestion is erroneously referred to as coprophagy. The cecotrophs areingested by the rabbit directly from the rectum as a result of a neurologiclicking response, and are swallowed whole without being chewed. Cecotrophyis influenced by light, ingestive patterns, and varies between captive andwild rabbits [37,38]. In wild rabbits most of the cecotrophy occurs duringdaytime when rabbits are within their burrows. This is in contrast to the situationin captive rabbits, where most of the cecotroph ingestion occurs atnight although it can occur at any time of the day or night [17]. Feed intakepatterns inversely follow cecotroph production—when cecotrophy is takingplace, food ingestion ceases. This is not a relationship that can be explainedby compensatory gastric fill or behavioral satisfaction, as applying collarsR. Rees Davies, J.A.E. Rees Davies / Vet Clin Exot Anim 6 (2003) 139–153 149(preventing the rabbits from ingesting their cecotrophs) does not alter thececotroph production or the food ingestion patterns [37].Hunger is stimulated by a number of factors including a dry mouth anddecreased blood levels of metabolites such as glucose, amino acids, and volatilefatty acids [12]. Cecotrophy usually follows about 4 hours after ingestionof food. Caged rabbits on a normal daylight pattern and fed ad libitumshow an increase in food intake from 3:00 to 5:00 PM, and food intakeremains high until midnight. There is then a decreased food intake until2:00 AM, followed by a further increase peaking at 0:600 AM and ending at0800 AM [4,19]. Cecotrophy therefore occurs mainly in the periods betweenmidnight and 02:00 AM, and again at 08:00 AM. When rabbits are fed arestricted feeding regime rather than ad libitum, cecotroph production isrelated to time of food ingestion and loses its influence from light signals[37]. The degree of cecotroph ingestion is directly related to the fiber contentof the ingested foods. Cecotroph ingestion is highest when rabbits are fed ona diet high in nondigestible fiber. Dietary fiber is distributed at a set ratiobetween hard feces and cecotrophs. Cecotrophs have around 50% of thecrude fiber level of the ‘‘hard feces.’’ This is regardless of the level of fiberin the food material. However, if dietary protein is restricted, the proteinlevel in the hard feces drops whilst that in the cecotrophs is conserved [8].

Resultados (español) 3:

Colon y reglamentación de Um el Fusus coli: anatomía y fisiologíaEl colon del conejo es divisible en un número de diferentes posicionesPiezas y morfológica.El colon ascendente es muy larga, y se divide en148 R. Rees Davies, J.A.E. Rees Davies / Vet Clin exot anim 6 (2003) 139 - 153Cinco extremidades extendiendo hacia delante y atrás separados por flexuras.La primera parteTiene tres taeniae formando tres filas de sacculations referido como ""haustrae." "En las partes segunda y tercera de la taeniae se combinan para un solo teniaY una fila de haustra.El resto del colon ascendente no tiene taeniae,Y mentiras en espiral en la parte dorsal de la cavidad abdominal.Fecal pelletsPrimero puede ser distinguido hacia el final del colon ascendente.La transversalColon es corto, y termina en un engrosamiento muscular, conocido como el ""fususColi, "" una estructura única para los lagomorfos.La separación del colon enDos piezas anatómicas y fisiológicas de la UM el Fusus coli ha conducido a un cambio de nombreDe estos como ""proximal" "y""distal "" colon, en lugar de usar la más tradicionalNomenclatura ascendente / transversal / descendente.El Um el Fusus coli es un diferencialMarcapasos para el inicio de las ondas peristálticas en tanto proximalY colon distal, y regula la separación (por las contracciones del taeniae / haustrae)De material fermentable de fibra no digerible [35].Los investigadoresUm el Fusus coli han demostrado correlaciones entre actividad y varios posiblesMecanismos reguladores, incluyendo las influencias nervioso autonomo y circulandoLos niveles de prostaglandinas, aldosterona, y otras sustancias.AldosteronaLos niveles son más altos durante la producción de heces duras.Sin embargo, no es claroSi esto es causa o efecto de la UM el Fusus coli actividad.Prostaglandinas hanSe ha demostrado que inhibe la motilidad del colon proximal y estimular laActividad en el colon distal, ayudando a la producción de caecotrophs [36].LaParticipación del sistema nervioso autonomo y glándulas suprarrenales en el ReglamentoDe la UM el Fusus puede ser la razón (en lugar de la inmunosupresión)Por qué los conejos son propensos a enfermedades gastrointestinales relacionadas con el estrés.Después de laUm el Fusus coli, el colon descendente y recto volver a simple forma tubularCon paredes más gruesas.La ingesta de alimentos y cecotrophy: la relatividad temporalCecotrophs son pellets producidos en el ano de los parcialmente fermentadosCuestión de el ciego y no de fibra no deseados.Porque no sonEl material de desecho, no son, estrictamente hablando, heces, aunque el término « fácilesHeces" "se usa como sinónimo de""cecotroph. "" el proceso de cecotrophLa ingestión es erróneamente denominado coprofagia.La cecotrophs sonIngerido por el conejo directamente desde el recto como consecuencia de un neurológicosLamiendo la respuesta, y deben tragarse enteros, sin masticar.CecotrophyEstá influenciado por la luz, los patrones de ingestivo, y varía entre los cautivos yLos conejos silvestres [37,38].En los conejos silvestres en la mayoría de los cecotrophy ocurre duranteEl día cuando los conejos son dentro de sus madrigueras.Esto es en contraste con la situaciónEn conejos cautivos, donde la mayoría de los cecotroph la ingestión se produce enLa noche, aunque puede ocurrir a cualquier hora del día o de la noche [17].La ingesta de alimentoModelos inversamente seguir cecotroph la producción cuando cecotrophy está tomandoLugar, la ingestión de alimentos cesa.Esto no es una relación que puede ser explicadoPor llenar de satisfacción compensatoria o de comportamiento gástrica, como la aplicación de collaresR. Rees Davies, J.A.E. Rees Davies / Vet Clin exot anim 6 (2003) 139 - 153 149(prevenir los conejos de ingerir sus cecotrophs) no altera laCecotroph patrones de producción o la ingestión de alimentos [37].El hambre es estimulado por una serie de factores, incluida una boca seca yLa disminución de los niveles sanguíneos de metabolitos como la glucosa, aminoácidos, y volátilÁcidos grasos [12].Cecotrophy sigue generalmente de alrededor de 4 horas después de la ingestiónDe alimentos.Jaula de conejos en un patrón normal de la luz del día y alimentados ad libitumMuestran un aumento en la ingesta de alimentos a partir de las 3: 00 a 5: 00 pm, y la ingesta de alimentosSigue siendo alto hasta la medianoche.Hay entonces una disminución en la ingesta de alimentos hastaA las 2: 00 am, seguido por un mayor incremento llegando a las 0600 am y finalizando enLas 8.00 am [4,19].Por lo tanto, cecotrophy ocurre principalmente en los períodos entreMedianoche y las 02: 00 de la madrugada, y de nuevo a las 08: 00 am.Cuando los conejos son alimentados con unaRégimen de alimentación restringida en lugar de ad libitum, cecotroph producción esRelacionadas con el tiempo de la ingestión de alimentos y pierde su influencia de señales luminosas[37].El grado de cecotroph ingestión está directamente relacionado con el contenido de la fibraDe los alimentos ingeridos.Cecotroph ingesta es mayor cuando los conejos son alimentados conUna dieta alta en fibras no digeribles.La fibra dietetica es distribuido en un conjunto cocienteEntre las heces y cecotrophs duro.Cecotrophs tiene alrededor del 50% de laNivel de la fibra cruda"hard heces. "Esto es independientemente del nivel de fibraEn la comida material.Sin embargo, si la proteina dietetica es restringido, la proteínaNivel en el duro heces gotas mientras que se conserva en la cecotrophs