1. Neurobiology of Appetite
Mechanisms Regulating Food Intake, Energy Expenditure, and Body Weight

2. ►energy intake (appetite)
Energy Balance
►energy intake (appetite)
► energy expenditure (basic metabolic rate, thermogenesis, and muscle action) .
Excess fuels are stored as fat and used later.

4. meat-type birds :↑ food intake, ↑ growth rate (BW) → meat production.
Layer-type chickens : ↓ food intake, ↓ growth rate (BW) → egg production
Commercial broiler breeder strains: ↑ leg problems, ↓ reproductive efficiency, etc.. → must be given a limited amount of feed to avoid overconsumption
it is important to understand the regulation
of feed intake and energy balance in poultry to develop
and better manage commercial lines of poultry.

5. Broilers as a model for studies of adipose metabolism and obesity:
1- Rapidly deposit abdominal fat.
2- Childhood obesity:
A-Excess fat deposition begins at hatch → juvenile period, prior to sexual maturation.
B-Adipocyte hyperplasia during the first several weeks of life in chickens.
3- Early stage of type 2 diabetes in humans :Chickens are naturally hyperglycemic → resistant to insulin.
4- Liver rather than adipose tissue is the primary site of lipogenesis In both chickens and humans, but not rodents.

6. Dual center hypothesis introduced by Stellar (1954)
Dual center hypothesis introduced by Stellar (1954). Hetherington & Ranson (1940), Anand & Brobeck (1951)

8. Cephalic phase hypothesis (Powley, 1977) PVN – nTS in hindbrain
Autonomic and endocrine hypotheses (Bray and York, 1979)
MONA LISA hypothesis (Bray, 1991) Most Obesities kNown Are Low In Sympathetic Activity.

11. Stress→ increases cortisol →increases glucose→ increases insulin→ decreases glucose→ increase food intake

22. Macronutrient Selection
Avoid consuming harmful or inappropriate foods
Consuming useful or essential foods
Sensing and sending to CNS
Evaluation and processing in the brain
Finally: induction of elective, macronutrient-specific appetitive drive (motivation), which results in the correct selection from a menu,

23. Strong mechanisms to defend proteins
Weak mechanisms to defend carbohydrates but strong attraction for consumption of sweet foods and a learned aversion when utilization is impaired
Lack of mechanisms to defend fatty foods but the existence of these mechanisms for essential fatty acids
Regulation of intake around a specific Carbohydrates: Proteins ratio in a wide range of insects, fish, rodents and chickens

24. GABAergic system: Oxytocin Nociceptin (NOFQ): LPS:
GABA; GABA A &GABAB receptors; GABA vs NOFQ; GABA vs NO; GABA vs NPY; GABA vs ghrelin; GABA vs Endocannabinoid system ; hypothalamic GAD 1 & GAD 2 gene expression in free feeding, fasting, fasting & refeeding states in broilers and layers.
Oxytocin
Nociceptin (NOFQ):
NOFQ vs Ghrelin
LPS:
LPS vs CRF; LPS vs COX1 & COX 2;; LPS vs hypothalamic CRF, POMC, TNF α, Serotonin 2c Receptors gene expression in broilers and layers.

25. Endocannabinoid System: CB1 & CB 2 receptors
Purinergic system: ATP; Adenosine
Ghrelin: Ghrelin vs brain stem GAD 1 GAD 2 gene expression; Ghrelin & macronutrient selection
Oxynthomudulin (OXM) OXM; OXM vs brain stem GLP-1 gene expression
Enterostatin Neurostroids