SALUD DEL TGI FUNCION PRINCIPAL DEL TGI

SALUD DEL TGI
FUNCION PRINCIPAL DEL TGI
Desde el punto de vista de la Nutrición Animal El
aparato digestivo puede presentar múltiples
variantes morfológicas; pero el proceso digestivo
tiene el mismo proposito en todos los animales:
CONVERTIR LOS GLÚCIDOS, LÍPIDOS Y PROTEÍNAS EN
UNIDADES MAS SENCILLAS, POR MEDIO DE LOS
MECANISMOS Y FACTORES INVOLUCRADOS EN LA
DIGESTIÓN y ASEGURAR UNA EFICIENTE ABSORCION
SALUD DEL TRACTO GASTRO
INTESTINAL : TGI
-
DIGESTION (accion mecanica por masticacion, accion quimica
por HCl, enzimas).
-
TRANSPORTE DE DIGESTA (contracciones peristalticas).
-
ABSORCION (transporte activo, pasivo,) nutrientes a la sangre).
-
SINTESIS (proteinas verdaderas, acidos grasos, carbohidratos,
vitaminas).
EXCRECION ( productos de desecho: por la bilis se excreta
toxinas, microbios, etc y por el recto se excreta calcio, magnesio
y fosforo)
-
IMPORTANCIA DE LA SALIVA
FUNCIONES DE LA SALIVA :
- SOLUBILIZACION de alimento seco
- LUBRICACIÓN Liga el alimento
formando bolo alimenticio.
- ENZIMÁTICA (Amilasa).
- BUFFER (Bicarbonato de Sodio)
- HIGIENE Oral
- ENFRIAMIENTO EVAPORATIVO de
algunas especies animales.
- CONTROL DE SECRECIÓN (volumen y
tipo) dependiente de sistema nervioso
central
SECRECION DE SALIVA & AGUA
Cantidad y composición de la
saliva varia considerablemente
entre especíes.
Cantidad relacionada al nivel
de actividad de masticar
Cantidad de secreción:
- PERROS
minima
(lubricacion, no enzimas).
- OVEJAS
3-10 litros/d
- CABALLO 10-12 litros/d
- VACUNO
130-180 litros/d
DIGESTION
•
•
•
Carbohidratos→ monosacaridos
Proteinas→ peptidos pequeños y aminoacidos
Lipidos→monogliceridos y acidos grasos
Digestión de los carbohidratos: Amilasa salival (boca) amilasa
pancreática (intestino delgado), disacaridasas(intestino delgado)
Digestión de las grasas: Lipasa pancreática
Requiere de la presencia de bilis.
Digestión de Proteínas: Pepsina en el estómago. Endopeptidasas de
origen pancreático y Exopeptidasas (carboxipeptidasa de origen
pancreático
DIGESTION EN VARIOS NIVELES
DIGESTION INTESTINAL :
Bilis hepática: sin fermentos emulsiona grasas rico en Na y K favorece el peristaltismo
intestinal, rebaja la tensión superficial del quimo, favorece la hidrólisis, impide la proliferación
de bacterias de la putrefacción y otros mcorg. Perjudiciales.
Jugo entérico: Amilasas, Proteasas y Lipasas
Jugo pancreática: Tripsina: Proteínas y péptidos en AA
Amilasa: Almidón e H.C. en azúcares
Lipasa: descompone grasas en a. grasos y glicerina. Máxima actividad con pH 8
DIGESTIÓN GÁSTRICA:
Ac. Clorhídrico
Pepsina: Proteínas = polipéptidos + péptidos + peptonas
Cuajo o renina: en lactantes, coagulación para facilitar la digestión
(nata, caseína y lactosa) y el suero: (lactosa, lactoalbúminas, NNP y sales minerales)
Lipasa: Actividad limitada por el bajo pH: Ac. Grasos + Glicerina
DIGESTION DE PROTEINAS
proteína del
alimento
polipéptido
diipéptido
proteína
indigestible
aa disponibles
masticación HCl pepsina tripsina quimiotripsina carboxipeptid. minopeptid. elastasas
DESARROLLO DE ENZIMAS
LECHON
DESARROLLO DE ENZIMAS
(unids/kg p.v. en intestino a los 10 días de edad)
POLLOS
DIGESTION EN CONEJOS
Reingestión
ALIMENTO
ABSORCIÓN
INTESTINO DELGADO
RESIDUO NO DIGERIDO
secreciones endógenas
partículas finas
CIEGO
partículas gruesas
AGV
HECES DURAS
HECES BLANDAS
DIGESTION EN EQUINOS
DIGESTION EN RUMIANTES
Producción diaria de saliva:
VACUNO: 150 l.; OVINO: 10 l.
Microorganismos anaerobios
CONTENIDO RUMINAL: en 3 Fases:
- Inferior: líquida y finas partículas
· Superior: más seca y partículas
groseras
· Agua: 850-930 g./Kg. MS
FERMENTACIÓN DE ALIMENTO
DIGESTIÓN QUÍMICA Y FÍSICA
· Masticación: 40-50 veces
Condiciones homeostáticas:
— pH: 5,5-6,5 (fosfato y bicarbonato de
la saliva y rápida absorción de
ácidos).
— Presión osmótica: próxima a la
sangre (iones)
· Tiempo de masticación: 8 h.
— Anaerobiosis: consumo rápido de
oxígeno
· Tiempo de rumia: 8 h.
— Temperatura: 38-42 ºC
m.o.
PRINCIPALES MICROORGANISMOS
ANAEROBIOS DEL RUMEN :
1. BACTERIAS
109-1010 por ml.
Más de 60 especies
Número y proporción según dieta
2. PROTOZOOS
106 por ml.
Mayor tamaño
Ciliados
- Grupos:
ISOTRICHIDAE U HOLÓTRICOS
· Isotricha y Dasytricha
· Ovalados
· No ingieren partículas ni celulosa
OPHYOSCOLECIDAE U OLIGÓTRICOS
· Entodinium, Diplodinium, Epidinium y
Ophryuoscolex
· Tamaño y forma variable
· Ingieren partículas y celulosa
QUE HACEN LOS m.o.
Funciones de los m.o. :
-digiere la fibra a AGV
-fabrica proteina
-fabrica vitamins K and B complex
La funcion del rumen es alojar microorganismos, similar en conejos y caballos cuy,
Syntetiza todas las vitaminas del C. B, excepto vitamin B12, que requiere Co para su sintesis
Syntetiza todas las vitaminas del C. B, excepto vitamin B12, que requiere Co para su sintesis
Produce amonio: Utilizado por los m.o. para formar AA´s, pueden absorver AA´s para formar proteinas,
pero parcialmente, satisfacen las necesidades de proteinas por digerir algunos m.o. Esto ocurre en el
abomaso e intestino delgado
Microorganismos en estomago convierte celulas vegetales en energia utilizable.
Celulosa es degradado por accion
microbiana.
Los Acidos Grasos Volatiles de Cadena
Corta (AGVCC) Aportan con el 6080% de la energia dietaria de
rumiantes (dependiendo de la dieta).
Grandemente absorvidos desde el
estomago en la circulacion portal
hepatica.
Pricipales SCFAs:
› Propionato: utilizado por el
higado (gluconeogenesis)
› Acetato utilizado para energia y
formar grasas
› Butirato utilizado para energia
RUMIACION
Rumia Comprende un ciclo de actividad de 4 fases : la regurgitación
de la ingesta seguida de una remasticación, reensalivación y nueva
deglución.
Esto logra disminuir el tamaño de partícula del alimento y aumentar la
superficie para la fermentación microbiana.
Ocurre principalmente cuando el animal descansa y no come.
DIGESTION FERMENTATIVA (FERMENTACION)
Todos los mamiferos tienen alguna capacidad fermentativa que les permite la
utilizacion de la fibra ingerida.
•
La importancia comparativa de la fermentacion esta relacionada a la fraccion de
la digesta total contenido en los compartamentos fermentativos del TGI i
•
Bacterias anaerobicas, protozoa y hongos producen enzymas que
degradan la cellulosa, hemicellulosa y pectina
Productos de la digestion fermentativa :
› Acidos grasos de cadena corta (SCFAs), tambien llamados acidos
grasos volatiles (VFAs)
› Gas metano
› CO2
› Amoniaco (NH3)
FERMENTACION EN MONOGASTRICOS
Limitada fermentación post gástrica (colon, recto y ciego)
TIEMPO DE TRANSITO EN EL TGI
Cantidad de tiempo que toma el
material para viajar de una parte
del intestino a otra.
Cuando el material viaja a traves del
intestino muy rapido, disminuye
el tiempo de transito intestinal.
Cuando el material viaja a traves del
intestino lento, se incrementa el
tiempo de transito intestinal.
ESTRUCTURA: BASE DE LA ABSORCION
The villi increase the surface area
of the ileum for the absorption.
The villi are finger like projections
into the lumen of the gut. The
villi increase the available surface
area by ten times.
The crypts contain the secretory
cells of intestinal secretion.
Mucosa is a mucus secreting
membrane.
The circular and longitudinal
muscles combine to create the
contractions known as peristalsis
that maintains the movement of
chyme along the alimentary
canal.
The serosa is a tough outer
membrane composed of collagen.
TRANSPORTE ACTIVO
Active Transport : Glucose absorption and Amino acids absorption into the
epithelial cells.
•Active mean that the membrane protein 'pump' requires energy to function
•The source of energy is ATP from respiration
•This moves the molecules from low to high concentration against the concentration
gradient
•The energy causes a shape change in the protein that allows it to move the
molecule to the other side of the membrane.
PARTICULARIDADES DE LA ABSORCION
Many substances in the diet are composed of small molecules that need little or no
digestion.
These include sugars, mineral ions, vitamins and water. These are absorbed by
different transport mechanisms:
•Cholesterol and the fat-soluble vitamins (A, D, E, K) are absorbed into the epithelial
cells of the ileum by lipid diffusion
•Mineral ions and water-soluble vitamins are absorbed by passive transport in the
ileum
•Dietary monosaccharides are absorbed by active transport in the ileum
•Water is absorbed by osmosis in the ileum and colon.
CLASIFICACION DE LOS ANIMALES POR SU INGESTA DE
ALIMENTOS PREFERIDO
1. Monogastricos ó norumiantes
2. Rumiantes o:
- Pre-gastrico
fermentacion (craneal)
- Post-gastrico
fermentacion (caudal)
FERMENTADORES PREGASTRICO
Clases
Rumiantes
Especies
Vacuno, oveja
Ciervo, antilope,
camello
Norumiantes
Mono colobine,
hamster
Kangaroo, hippo
Habito dietario
herbivoros q pastan
herbivoros selectivos,
incluyendo folivores and
frugivores
herbivores selectivos
Herbivores selectivos y que
pastan
FERMENTADORES POSTGASTRICO
Clases
Especies
Digestores cecal Capybara
Conejo
Rata, raton
digestores
colonicos
Sacculados
Unsacculated
Elephant, caballo, zebra
Monos del nuevo mundo
cerdo, humano
Panda
Perro, gato
habito dietario
Pastan
herbivores selectivos
Omnivoros
Pastan
Folivoros
Omnivoros
Herbivoros
Carnivoros
FERMENTACION COMPARATIVA POR ESPECIES
CAPACIDAD DIGESTIVA COMPARATIVA
SALUD DEL TGI
Integridad anatómica y fisiológica (Estructura y Función).
Microbiota del TGI: parte integral de la salud del TGI e influencia el desarrollo de
la microanatomia, ayuda a los procesos digestivo, estimula el desarrollo del sistema
inmune entérico y puede proteger contra la invasión de patógenos.
Sistema inmune mucosal: la mucosa intestinal tiene una función de barrera, pero
también puede generar una respuesta inmune protectiva contra patógenos. El TGI
alberga el mas grande numero de células inmunes en el cuerpo.
Fotos de: Collet, S. University of Georgia - 2008
Tabla 2. Cantidad de bacterias (log CFU/g) en el tracto intestinal del pollo
en diferentes edades.
CRECIMIENTO ALOMETRICO
Tabla 1: Ingredientes y problemas potenciales en dietas para pollos sobre
la salud intestinal
INTEGRIDAD DEL INTESTINO
El TGI constituye una extensa superficie en la que se produce un CONTACTO ÍNTIMO entre
el organismo y las substancias de la dieta, microorganismos, parásitos y toxinas exógenas.
El intestino permite el PASO DE SUSTANCIAS a la circulación sistémica, pero al mismo tiempo
EXCLUYE COMPUESTOS PATÓGENOS (Gaskins, 1997).
El TGI tiene múltiples MECANISMOS DE DEFENSA inespecíficos e inmunológicos.
Los mecanismos no específicos incluyen producción de ácidos gástricos, peristaltismo, capa
mucosa, estrecha unión entre las células epiteliales, proteo lisis, resistencia contra la
colonización por bacterias patógenas y el eje intestino hepático.
La defensa inmunológica del intestino delgado incluye la PRODUCCIÓN DE
INMUNOGLOBULINAS secretoras, células M y linfocitos (Madara et al. 1990; Walker y
Owen, 1990; Deitch, 1993; Wang, 1995).
Los INDICADORES comúnmente usados para evaluar la integridad intestinal son la longitud
de las vellosidades, profundidad de las criptas y número de células caliciformes,
permeabilidad transepitelial, actividad enzimática de la superficie ciliada, inflamación y
crecimiento
del
animal.
INTEGRIDAD INTESTINAL (I.I.)
(Cervantes, Phibro Animal Health Corp. EUA, 2011)
Desarrollo completo, macroscópico y microscópico, a la integridad
ininterrumpida y al funcionamiento normal del tubo intestinal.
La I.I. optima es, desde el nacimiento hasta el final del ciclo productivo, es
esencial para obtener el MÁXIMO POTENCIAL GENÉTICO de crecimiento
y utilización eficiente de los nutrientes del alimento en base a un TGI
saludable, una altura máxima de la villi, maxima densidad de la villi y
máxima área absortiva.
Es necesario estimular un desarrollo temprano, integro y completo del
aparato GTI, glándulas y órganos anexos para maximizar la digestión y
absorción de nutrientes.
integridad del intestino manteniendo su ESTRUCTURA Y FUNCIÓN o
simplemente un intacto y sano intestino (Dr. Harish V. Dharne, head of
Avitech’s).
Higher villi in the jejunum (p<0.01) were seen when Bacillus
subtilis-based probiotics were used compared to diets without this
additive
VD was higher when probiotics based on Bacillus subtilis were used together with prebiotics
based on MOS, compared to the use of probiotics based on Bacillus sp alone. It was also
higher in the birds fed the probiotics containing a bacterial pool compared to those
containing only one culture (probiotic 1). The results suggest that, in order to obtain higher
VD (consequently higher nutrient absorption area), it is necessary to use MOS-based
saccharides when probiotics based in only one bacterial culture are used. On the other
hand, they would be not necessary if the probiotics has many bacterial cultures, as
observed for probiotic 2.
IMPORTANCIA DE LA INTEGRIDAD
INTESTINAL (I.I.)
FACTORES QUE AFECTAN LA I.I.
CAUSA MAS COMUNES DE LA MALA I.I.
AGENTES ETIOLOGICOS MAS COMUNES DE LA
ENTERITIS
RECOMENDACIONES NUTRICIONALES
Acceso rapido de agua y alimento de buena calidad, para favorecer el desarrollo
y maduracion precoz del tubo intestinal .
Verificacion diaria del consumo (agua y alimento) mediante la palpacion del
buche.
Uso de enzimas para mejorar digestibilidad y reducir la viscocidad de cereales
con contenido alto de polisacaridos no almidonados.
Verificacion y rechazo de materias primas para la fabricacion de alimentos
contaminados con micotoxinas o aminas biogenicas.
Evitar el uso de grasas rancias o no estabilizadas con antioxidantes o que no
cumplan con los requisitos de calidad.
Evitar el uso de soya mal procesada con contenido alto de inhibidores de tripsina.
Maintaining Gut Integrity
By Dr. Harish V. Dharne, head of Avitech’s Business Promotion and
Knowledge Resource Centre
Nutrition and gut health are closely related in commercial poultry
production.
Diet formulation and feed management can have a marked effect on gut
health greatly influencing nutrient utilization and growth of the animal. Gut
health problems arise due to improper nutrition and an unhygienic
environment especially during the early stages of chick development.
For cost effective and sustainable commercial operations there is need to:
1. Maintain natural gut health through proper nutrition and a clean
environment, and
2. Effective treatment of an existing gut disorder.
TGI: FUNCION Y ESTRUCTURA
To improve gut health, a clear understanding of the STRUCTURE AND FUNCTIONALITY OF
THE GUT is important..
Birds also have high numbers of intestinal villi and high EPITHELIAL TURNOVER RATE (48 TO
96 H), and rapid inflammatory response (less than 12 hours, as compared to 3-4 days in
mammals), which makes them more susceptible to disturbances in absorptive capacity than
mammals.
Transit time and pH in poultry GIT
GIT Segment
Transit Time(Min)
pH
Crop
50
5.5
Proventriculus / gizzard
90
2.5-3.5
Duodenum
5-8
5-6
Jejunum
20-30
6.5-7.0
Ileum
50-70
7.0-7.5
Colon
25
8.0
Source: R.Gauthier(2002)
Natural Physical Barriers that Help to Maintain
Intestinal Integrity
Physical barriers protect against the entry of foreign materials and organisms into the
bloodstream and access to other viscera thus helping intestinal integrity. On occasion due to
improper nutrition or an unhygienic environment, when the load of foreign invaders increase
these barriers are breached.
1. Mucus (a protective1. Mucus: material secreted by intestinal cells) is a barrier to bacterial and
fungal invasion. It is broken by some enzymes (eg. mucinolytic, urease). Poultry feeds with
under cooked soy meal may contain urease.
2. Gut epithelial cells (enterocytes): These cells form a semi-permeable surface that selectively
allows passage of fluid, electrolytes, and dissolved nutrients. Every epithelial cell in the
digestive tract is part of a continuous physical barrier. When organisms and toxic agents
damage epithelial cells, the integrity of this protective barrier is broken.
3. Fluid secretion: fluid having large amounts of water mixed with electrolytes. The fluid in the
upper small intestine is protective and keeps bacteria in suspension and washes them
downstream.
4. Vascular supply: supply under the gut epithelial layer serves to rapidly dilute and carry away
any agents or chemicals (endogenous or exogenous) that may breach the mucosal barrier.
Factors Influencing Gut Integrity
a. Physical barriers: Intestinal integrity is compromised when the mucus layer is
degraded; epithelial cells are effaced or destroyed, the vascular supply is
interrupted, or the immune system is compromised. Viruses, bacteria, fungi,
parasites, and toxins can damage this.
b. Stress factors: Gut environment is also altered by several stress factors to the birds
like handling, transportation, overcrowding, abrupt changes in environment etc.
c. Feed toxins and toxicants: Feed toxins and toxicants can also affect the gut
integrity.
d. Dietary factors: Nutritional deficiency due to imbalance in ration formulation, grain
engorgement, microbial load in feed etc. affect gut health. The nature of the diet,
for example presence of non-starch polysaccharide (NSP) especially soluble
fractions in the diet provide substrate for the growth of undesirable bacteria and
accumulation of fermentation products affecting the gut severely. Insoluble NSP is a
major problem leading to soiling of litter.
e. Health status: Diseases like coccidiosis and fowl plague are found to affect the gut
integrity severely. Infections, injuries etc. also affect gut health.
f. Gut micro flora: The rich bacterial community that make up the gut micro flora play
an important role for the host through changes in the morphology of gut, nutrition,
pathogenesis of enteric diseases, immune response and alterations in colonization
resistance. The shift in composition of this microflora results in production and
efficiency losses often in the absence of any clinical signs. Useful microbes
(commensal bacteria) in gut play a positive role in controlling the gut flora and
stimulate the development of the gut wall. Hence, microbial balance of gut is utmost
important in maintaining gut integrity.
g. Beak deformity: Beak deformity preventing proper feed consumption may impair
gut health.
Early Chick Nutrition and Gut Health
Good start is an important factor in MAXIMIZING PROFITS from broiler operations.
Early nutrition mainly in the first 7 days of life for broilers may program the birds' systems and set a pattern
for growth and productivity. A large percentage of early growth (2 to 5 times the growth rate of other
tissues) occurs in the digestive tract and those organs involved in digestion.
If digestive growth is retarded during this time period, overall growth rate may be compromised. Further
newly hatched chicks are more prone to gut infections as its natural defense is yet to be strengthened. So
proper care should be taken during this time period.
Feeding of chicks:
Access to nutrients post hatch has a major impact on the immediate and long-term development of the chick.
The immediate post hatch period is critical for the development of all systems in chicks including the immune
system.
The development of bursa and spleen is responsive to environmental stress at an early age in chicks.
Delayed access to nutrients post hatch reduces the relative weight of bursa and spleen.
The passage of feed that is not sterile, through TGI exposes the bursa to a variety of antigens. So the earlier
the chicks are fed post hatch, the sooner will the proliferation stem cell meet environmental antigens. This
clearly suggests that early nutrition is important in laying a strong foundation for the health status of birds in
a situation where little or no antibiotics are allowed in their feed. Suitable feed additives should be added
in the starter diet as precautionary measure that will ensure better health and productivity.
Role of Dietary Factors in Improving Intestinal Integrity
Quality feed ingredients: Supplementation of quality feed ingredients helps in
maintaining natural gut health.
Processed feed: Many incriminating factors of feed are destroyed due to
processing. Extrusion is effective in reducing microbial contamination in feedstuffs
and in Salmonella control.
Pelleted feed: Pelleting provides scope for utilization of high fibre feed resources.
Use of steam- pelleted feed seems to be of value in maintaining gut health.
Feed additives: Commercial poultry production during the last 50 years has
benefited from pharmaceutical and biological products that enabled flock size to
increase, genetic potential and improved nutritional formulations to be realized, and
overall production to increase. Food animal agriculture is providing wholesome
poultry meat protein for consumption in the human diet at unprecedented levels.
Some feed additives that promote the gut health either directly or by preventing
the enteric pathogens are discussed below
ADITIVOS QUE PROMUEVEN SALUD DEL TGI
ANTICOCCIDIALS AND IONOPHORES; coccidiosis, a managemental disease, causes devastating losses to
the poultry industry. The disease is characterised by an invasion and damage of the intestinal wall by the
parasite resulting in severe haemorrhage and mortality. For this reason, it is essentially added in most
poultry rearing situations during the rearing period to prevent illness and control infections. When used in a
structured and monitored programme, anticoccidial agents are very effective and permit the optimum
performance of the animal without compromising health status. No new anticoccidial agent has come onto
the market since the 1980s, which is in part a reflection of the success that the ionophores have brought to
the control of the disease.
PROBIOTICS (DIRECT-FED MICROBIALS); “A probiotic is defined as a live microbial feed supplement which
beneficially affects the host animal by improving its INTESTINAL MICROBIAL BALANCE.”
Gut flora may be disturbed under several circumstances including the use of antibiotics or other drugs,
excess stress, disease, exposure to toxic substances, which allows harmful competitors to thrive in the gut.
Probiotics prevent such harmful bacteria (enteric pathogens) from growing in the gut and thus minimize the
disturbances caused by them, and also maintain host favourable bacteria. Thus Probiotics balance gut
microflora.
Probiotics are also used as an alternative to antibiotics. However, probiotics are not a substitute for
antibiotics in birds with serious infections but are useful in restoring the normal bacterial population that was
otherwise altered due to administration of antibiotics. If the conditions that originally caused damage to the
natural gut flora persist, the benefits obtained from probiotic supplements will be short lived.
PREBIOTICS; are non-digestible food ingredients (readily fermentable
sugars), that beneficially affect the host by selectively stimulating the
growth and/or activity of one or a limited number of bacteria in the colon,
and thus improve host health. Most potential prebiotics are carbohydrates
(such as oligosaccharides). Prebiotic oligosaccharides may be added to
processed foods. Some prebiotics that are used in this manner against
pathogens are fructo-oligo-saccharides (FOS), xylo-oligo-saccharides
(XOS), mannan-oligo-saccharides (MOS) and galacto-oligo- saccharides
(GOS).
SYNBIOTICS; although use of probiotic formulations may well help in
achieving these benefits, it is also possible to increase and maintain a
healthy bacterial gut flora by increasing the amounts of prebiotics in the
diet such as inulin (naturally occurring oligosaccharides), raw oats, and
unrefined wheat. As probiotics are mainly active in the small intestine
and prebiotics are only effective in the large intestine, the combination of
the two gives a synergistic effect. Appropriate combinations of pre- and
probiotics are termed as synbiotics.
ACIDIFIERS/ORGANIC ACIDS; include short chain fatty acids, volatile fatty acids and
weak carboxylic acids that are only partly disassociated. They may play a role in
maintaining gut integrity in the way that they reduce the colonization of pathogens (like
Salmonella and E.coli) in intestinal wall by lowering the intestinal pH below 6.0, and
promoting the normal microflora growth. This condition also increases the efficiency of
all digestive enzymes. Daily application of short chain fatty acids such as Butyric acids
increases epithelial cell proliferation, quick repairing of the intestine, increased villous
height and in turn increased absorptive capacity. Alone or in combination, these are
beneficial to the animal's health.
ENZYMES; extra enzymes can add to the animals' own digestive capacity. Feeding
high viscosity cereal grains to broilers result in larger microbial populations in the ileum.
Viscosity reduces the passage rate of the feed leading to overall reductions in
consumption and decreased performance, sticky droppings and dirty eggs. A viscous
environment slows down digestion processes, and encapsulates nutrients, making them
inaccessible to digestive enzymes. Viscous gels are formed in the digesta by the
soluble NSP, which are not digested by the animal's own enzymes. Thickening of
unstirred water layer due to gel formation also inhibit absorption. Thus non-starch
polysaccharides form a major target substrate for feed enzymes. The addition of
enzymes to address NSP viscosity can improve gut health, feed efficiency, improve
manure quality and facilitate the use of lower cost feed ingredients.
TOXIN BINDERS; are used through feed to bind or adsorb deleterious
substances such as mold and fungi-borne mycotoxins. These are the invisible
thieves or a hidden danger in animal feed, to animal health and production.
They may also accumulate in animal products and contaminate the human
food chain.
ANTIBIOTIC GROWTH PROMOTERS; With the intensification of livestock
farming the use of antibiotics for growth promotion has become popular.
Antibiotic growth promoters are feed additives that are administered at a
low, sub therapeutic dose to suppress sensitive populations of bacteria in the
gut and improve growth and performance of bird. The reason is that a
reduction in gastrointestinal infections would result in the subsequent increase
in muscle weight. It has been estimated that as much as 6 per cent of the net
energy in the diet could be lost due to microbial fermentation in the intestine
(Jensen, 1998) and stimulation of energy-consuming immune responses. If the
microbial population could be better controlled, it is possible that the lost
energy could be diverted to growth. Whatever the mechanism of action, the
result of the use of growth promoters is an improvement in daily growth rates
between 1 and 10 per cent resulting in meat of a better quality, with less fat
and increased protein content
Limitaciones del uso de los antibioticos:
An overuse of any antibiotic over a period of time may lead to the local
bacterial populations becoming RESISTANT TO THE ANTIBIOTIC.
ANTIBIOTIC RESIDUES in the products may affect humans.
Essentially, there are two main ways in which we can reduce our
dependence on antibiotic use in animals:
1. An obvious choice is the development of ALTERNATIVES TO ANTIBIOTICS
that work via similar mechanisms, promoting growth whilst enhancing the
efficiency of feed conversion.
2. A more difficult route would be to IMPROVE ANIMAL HEALTH.