"عسى ان تكون علما ينتفع به" Feed intake poultry Water intake poultry Control appetite in poultry

1. Control of Feed and Water Intake
in Poultry

2. Plan of Talk
 Control of food intake
– Appetite control
– Feeding rhythms
– Factors determining appetite
 Control of water intake

3. Plan of Talk
 Control of food intake
– Appetite control
– Feeding rhythms
– Factors determining appetite
 Control of water intake

4. Nervous Control
1. Ascending signals are originated from:
– The food itself such as color, shape and smell.
– The intestinal tract following ingestion of food via receptor cells
sensitive to such parameters as taste, osmotic pressure, mechanical
pressure and some metabolites.
2. These signals are transmitted to the hypothalamus.
3. Descending signals arise from the hypothalamus to transmit
information to digestive system organs as gizzard, liver,
intestine and pancreas.

5. Appetite Control
 There are many different mechanisms which are implicated in
the control of appetite;
1. Feeds shape
2. Feed smell
3. Feed color
4. Feed taste
5. Physical signals
6. Metabolic signals
7. Osmotic pressure

6. 1- Feed Shape
 Birds are sensitive to feed shape.
 Once they have become used to one particular form of
presentation of food, a certain amount of adaptation is
necessary if another is provided.
– A bird fed on pellets will need a few days acclimatization before being
able to eat the same quantity of food if it is changed to meal or whole
grains.

7. 2- Feed Smell
 Birds are less sensitive to smell, or at least less than
mammals.
 Some experiments demonstrated that birds are able to
discriminate between feeds they prefer, and those they do
not, through the odor.
 This phenomenon could explain certain instances of
inappetance and could be used in experiments in the
detection of anti-nutritional factors.

8. 3- Feed Color
 Color seems to have little influence in birds.

9. 4- Feed Taste
 Amongst ascending signals originating from the intestinal
tract, the initial one is based on feed taste.
 Generally, birds are less sensitive than mammals to those
substances capable of increasing (sugar, aromas) or, on the
other hand, decreasing (bitter) intake.
 One of the best known examples is that of rape seed meal,
where the bitterness will have a far greater effect with pigs,
cattle and rodents than with birds.

10. 5- Physical Signals
 There are number of receptors allocated within the crop and,
to a lesser extent, the remainder of the intestinal tract.
 These receptors are sensitive to the physical pressure to
which they are subjected.
 Once stimulated, messages sent to the brain are integrated
into the signal for satiety.

11. 6- Metabolic Signal
 In addition to physical signals, some metabolic signals are also
present.
 The best known metabolic signal is glucose, which has given
rise to the glucostatic theory of appetite;
1. Hypoglycaemia stimulates a nervous centre for intake (hunger)
2. Hyperglycaemia stimulates a centre for satiety.
– These centers are located in the hypothalamus.

12. Cont. …
 Some metabolites also have a role, including:
1. Amino acids
2. Non-esterified fatty acids
 These metabolites role seems to be less important than that
of glucose.
 Deficiency of some amino acids, particularly tryptophan, has a
major effect on appetite by limiting food intake.
 Similar responses are obtained with some excessive
imbalances.

13. 7- Osmotic Pressure
 Infusion of solutions with high concentrations of potassium
chloride or sorbitol into the crop or the duodenum slows
down the rate of food intake.

14. Plan of Talk
 Control of food intake
– Appetite control
– Feeding rhythms
– Factors determining appetite
 Control of water intake

15. Feeding Rhythms
 Domestic birds consume their food regularly throughout the
day, they do not eat discrete meals.
 This behavior is related to lightening, although birds may be
able to consume modest amounts under dim conditions.
 Slight increase in feed intake is recorded at the beginning and
the end of the light period.
 Under continuous lighting conditions, the pattern of intake is
constant whatever the time.

16. Cont. …
 In laying hens, a peak in feed consumption is observed at the
end of the day which is particularly pronounced if the hen is
in the phase of calcification of the egg to be laid the following
day.
 In practice it is essential that calcium is supplied separately at
the end of the day or, in the case of restriction, the compound
diet is offered at the end of the day.

17. Plan of Talk
 Control of food intake
– Appetite control
– Feeding rhythms
– Factors determining appetite
 Control of water intake

18. Factors Determining Appetite
1. Energy; feed concentration and bird requirements
2. Bulk of the diet
3. Protein Concentration in Feed
4. Minerals
5. Vitamins
6. Feed particle size

19. 1- Energy
Concentration : Requirements
 Appetite of birds is closely linked to their energy
requirements.
– This is explained by the fundamental role played by metabolic signals,
for example hypo and hyperglycaemia.
 Birds attempt to consume quantity of food necessary to meet
their energy requirements.
 Factors that will increase or decrease energy balance will
definitely increase or decrease appetite.

20. Cont. …
 As a consequence, one of the characteristics of the diet which
has the greatest effect on intake is its energy concentration.
– A diet low in metabolizable energy will therefore increase
consumption.
– The reverse is seen when energy concentration is high.

21. Cont. …
 This homeostatic mechanism of consumption is rarely perfect;
– Laying hens can adjust their energy consumption as a consequence of
dietary energy concentration.
– Broiler breeders are unable to reduce their intake adequately when
dietary energy concentration increases.
 There are other dietary factors which have a role;
– In the species Gallus, it is the smaller birds that are most capable of
maintaining energy intake constant with fairly large variations in
dietary energy concentration.
– On the other hand, heavy genotypes tend to maintain intake constant
irrespective of dietary energy concentration.

22. 2- Bulk of the Diet
 The physical presentation of feed and its effect inside the
gastro-intestinal tract has a significant.
– The presence of large amounts of plant cell wall constituents within
the feed explains the effect of bulk on the limitation to intake.
– On the other hand, feed presentation in the form of pellets will reduce
this effect and allow a more accurate adjustment to energy
consumption.

23. 3- Protein Concentration in Feed
 The concentration of protein in the feed has a little effect on
intake.
 In this context, it is essential to distinguish between:
1. Productive birds (laying hens, young growing birds)
2. Adults at maintenance.
3. Growing birds

24. Cont. …
Productive birds
 Any change in dietary protein concentration might alter the
level of production and, as a result, change energy
requirements, and therefore intake.

25. Cont. …
Adults at maintenance
 Concentration of dietary protein has no effect on appetite
even if it approaches zero.
 High levels of protein can lead to inappetance.
 This effect may be explained by the saturation of the
mechanisms of degradation of amino acids which result in
excessive levels of uric acid.

26. Cont. …
 When offered a choice between feed with different levels of
protein that are very low or very high, most birds prefer the
very low even if it is protein free.
 Certain amino acids imbalances (deficiencies or excess) may
influence appetite

27. Cont. …
Growing birds
 When energy requirements are met, an excess of dietary
protein will result in a moderate reduction intake without
altering growth rate.

28. 4- Minerals
 Minerals may also influence appetite.
 Deficiencies as well as excesses of sodium, chloride and
calcium will reduce intake significantly.
 Between these two situations, these minerals do not seem to
have any effect.
 Deficiencies in trace minerals will not affect appetite unless
they are prolonged.

29. 5- Vitamins
Growing birds
 Most vitamin deficiencies will reduce feed intake.
Adult birds
 Vitamin deficiency has no effect in adults as long as other
effects of the deficiency are not apparent.

30. 6- Feed Particle Size
 Texture as well as pelleting may influence intake.
 If the diet is offered as a meal, consumption will diminish in
young bird when particle sizes are small.
 If the mean diameter is below 800 microns, this response
becomes clearly noticeable.
 The depressive effect is proportional to the reduction in mean
diameter of the particles;
– On average each reduction of 100 microns is associated with a
decrease in intake of 4%.
 Finely ground feeds are poorly consumed by poultry.

31. Plan of Talk
 Control of food intake
– Appetite control
– Feeding rhythms
– Factors determining appetite
 Control of water intake

32. Water : Feed Intake
Water restriction
 There are close links between drinking and food intake.
– A restriction in water provision is associated with a reduction in food
intake.
 Water restriction should not be used as a means of limiting
food intake because of the variable response between
individual birds and the risks of alterations in renal function.

33. Cont. …
Feed restriction
 Feed restriction is often associated with an increase in water
intake, after a few days of acclimatization, which may result in
a deterioration in rearing conditions as wet litter.
– Thus it might be necessary to limit the amount of water available if
food restriction is being considered.

34. Control of Water Intake
 Water intake is controlled by the hypothalamus through the
osmotic receptors.
– These receptors are located in the anterior region of the
hypothalamus in the preoptic region.
 Endogenous opiates control water intake through an
inhibitory effect whilst an antagonist such as naloxone
stimulates water consumption.
 Serotonin and dopamine do not appear to be implicated.

35. Cont. …
 Birds possess the specific physiological ability of re-absorbing
water from urine; this travels back up the colon, which is the
site of water re-absorption resulting in the precipitation of
uric acid in the form of urates which are whitish particles
recovered in the excreta.

36. Cont. …
Water consumption and feed mineral content
 Water consumption may be influenced by the nature of the
diet offered to birds.
– High dietary concentrations of sodium or potassium are associated
with increased intake.
– Diets containing 0.25% sodium will increase water consumption by
10% compared with those containing only 0.14%.
– Manipulation of dietary mineral levels is therefore a practical means of
controlling litter moisture content.

37. Cont. …
Water Consumption and protein concentration
 Dietary protein levels may equally modify water intake;
– Diets with high levels of protein result in a slight increase in water
intake, this may be explained by the mechanisms of excretion of uric
acid via the kidney.
– Dietary increase of 1% protein is associated with an increase in water
consumption of 3%.

38. Cont. …
Water consumption and ambient temperature
 Water consumption may increase by 15% in summer when
compared with winter.
 Ambient temperature has a significant effect on water
consumption.
– This is related to the thermoregulation mechanisms in order to
dissipate latent heat.
– When ambient temperature increases, thermoregulation mechanisms
are considered an important energy losses
– Birds try to save these energy losses by consumption of water.