scholarly journals Review: Control of feed intake by hepatic oxidation in ruminant animals: integration of homeostasis and homeorhesis

animal ◽  
2020 ◽  
Vol 14 ◽  
pp. s55-s64 ◽  
Author(s):  
M.S. Allen
Keyword(s):  
Feed Intake ◽  
Hepatic Oxidation ◽  
Ruminant Animals

Drives and limits to feed intake in ruminants

2014 ◽  
Vol 54 (10) ◽  
pp. 1513 ◽  
Author(s):  
Michael S. Allen
Keyword(s):  
Feed Intake ◽  
Feeding Behaviour ◽  
General Circulation ◽  
Physiological State ◽  
Vagal Afferents ◽  
Energy Status ◽  
Hepatic Oxidation ◽  
Ruminant Diets ◽  
Lactation Cycle ◽  
Osmotic Effects

The control of energy intake is complex, including mechanisms that act independently (e.g. distention, osmotic effects, fuel-sensing) as well as interacting factors that are likely to affect feeding via their effects on hepatic oxidation. Effects of ruminant diets on feed intake vary greatly because of variation in their filling effects, as well as the type and temporal absorption of fuels. Effects of nutrients on endocrine response and gene expression affect energy partitioning, which in turn affects feeding behaviour by altering clearance of fuels from the blood. Dominant mechanisms controlling feed intake change with physiological state, which is highly variable among ruminants, especially through the lactation cycle. Ruminal distention might dominate control of feed intake when ruminants consume low-energy diets or when energy requirements are high, but fuel-sensing by tissues is likely to dominate control of feed intake when fuel supply is in excess of that required. The liver is likely to be a primary sensor of energy status because it is supplied by fuels from the portal drained viscera as well as the general circulation, it metabolises a variety of fuels derived from both the diet and tissues, and a signal related to hepatic oxidation of fuels is conveyed to feeding centres in the brain by hepatic vagal afferents stimulating or inhibiting feeding, depending on its energy status. The effects of somatotropin on export of fuels by milk secretion, effects of insulin on gluconeogenesis, and both on mobilisation and repletion of tissues, determine fuel availability and feed intake over the lactation cycle. Control of feed intake by hepatic energy status, affected by oxidation of fuels, is an appealing conceptual model because it integrates effects of various fuels and physiological states on feeding behaviour.

Current understanding of the role of the reticulum and reticulo-omasal orifice in the control of digesta passage from the ruminoreticulum of sheep and cattle

1998 ◽  
Vol 78 (1) ◽  
pp. 15-21 ◽  
Author(s):  
E. K. Okine ◽  
G. W. Mathison ◽  
M. Kaske ◽  
J. J. Kennelly ◽  
R. J. Christopherson
Keyword(s):  
Feed Intake ◽  
Physiological Status ◽  
Electromyographic Activity ◽  
Solid Meal ◽  
Voluntary Feed Intake ◽  
Rate Limiting Step ◽  
Ruminant Animals ◽  
Bilateral Vagotomy ◽  
Digesta Passage ◽  
Pressure Changes

Simultaneous abolition of the motility of the ruminoreticulum (RR) and digesta passage from the RR by bilateral vagotomy indicate that the motility of the RR coordinated with quiescence of the reticulo-omasal orifice (ROO) are prerequisite for caudal movement of digesta from the RR and forestomach. Rate of passage is of importance in ruminant animals since it is related to maximal voluntary feed intake, extent of digestion of the diet, amount of protein which bypasses the rumen, efficiency of microbial growth, extent of methane loss, and susceptibility of animals to bloat. In a series of studies, we clarified the roles of frequency, pressure and duration of reticular contractions and the function of the ROO in controlling digesta flow from the rumen in response to changes in diets, environmental conditions and physiological status. Variability in amount of NDF and OM transferred per contraction suggests that frequency of reticular contraction is not the rate-limiting step in digesta passage from the rumen. This concept is supported by our finding that the relaxation of the ROO is not always coincidental with reticular electromyographic activity in solid meal-fed relative to milk fed sheep. The magnitude of reticular pressure may not precisely control digesta passage through the ROO as the amount of OM and NDF associated with each centimetre of pressure during contraction varies from 1.2 to 1.4 and from 0.9 to 2.5 g. On the other hand, the amount of OM and NDF passed per second of reticulum contraction varies only from 0.3 to 0.6 and from 0.2 to 0.3 g, respectively, in cattle. In addition, a 38% decrease in mean retention time of particulate matter in the rumen was associated with a 14% increase in duration of reticular contraction in cattle. Similarly, quiescence of the ROO increased from 2.9 to 3.3 s in sheep when feed intake increased from maintenance to twice maintenance. We suggest that duration of reticular contractions may be more closely related to digesta flow than is either frequency or pressure changes. We also suggest that the ruminant animal can influence reticular contraction characteristics and duration of the quiescence of the ROO in response to various stimuli and that reticular contractions are coordinated with other diet and physiological demands for optimal transfer efficiency of digesta from the RR. Key words: Digesta passage, reticular contractions, reticulo-omasal orifice, electromyographic activity

Nutritional assessment and feed intake of microparticulate diets in crustaceans and fish

2000 ◽  
Vol 31 (8-9) ◽  
pp. 691-702 ◽  
Author(s):  
S Teshima ◽  
M Ishikawa ◽  
S Koshio
Keyword(s):  
Feed Intake ◽  
Nutritional Assessment

Potensi Covercrop Kebun Sawit Sebagai Sumber Pakan Hijauan Ternak Ruminansia Pada Musim Kemarau di Pelalawan, Riau

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Ruslan A. Gopar ◽  
S. Martono ◽  
Muhamad N. Rofiq ◽  
Windu N.
Keyword(s):  
Cover Crops ◽  
Oil Palm ◽  
Dry Matter ◽  
Sampling Method ◽  
Dry Season ◽  
Forage Production ◽  
Destructive Sampling ◽  
Matter Production ◽  
Ruminant Animals ◽  
Line Intercept

The objective of this experiment was to obtain forage/ cover crops productivity and carrying capacity for ruminant animals in Pelalawan Regency, Riau in the dry season. Data were collected from civil palm oil plantations at the aged 7, 10 and 14 years in the end of dry season with a destructive sampling method. Sampling used line intercept method which every hectare were picked 10 points by using a pair of 1 m2 sized quadrant. The result showed that the number of vegetations/ cover crops in oil palm plantations aged 7, 10 and 14 years was 42 types.The proportion of forage which consist grass, legume and ferns was diverse at each age of oil palm plantations. Forage production under oil palm plantations aged 7, 10 and 14 years were 2,571 kg/ha, 1479.76 kg/ha and 1417.22 kg/ha as fed and amounted to 811.41 kg/ ha, 471, 15 kg/ ha and 456.91 kg/ ha in the dry matter production. Average carrying capacities of oil palm plantations aged 7, 10 and 14 years was 0.36 Animal units (AU)/ha/year, 0.21 AU/ha/year and 0.20 AU/ ha/year.Penelitian ini bertujuan untuk mengetahui potensi jumlah covercrop dan kapasitas tampungnya di kebun sawit sebagai sumber pakan hijauan ruminansia pada musim kemarau di kabupaten Pelalawan, Riau. Pengambilan data dilakukan di perkebunan kelapa sawit yang berumur 7, 10 dan 14 tahun milik rakyat pada akhir musim kemarau. Pengambilan sampel dengan destructive sampling method menggunakan metode garis berpetak memakai kuadran berukuran 1m2 dengan jumlah sampel tiap area sebanyak 10 titik. Berdasar hasil pengukuran diperoleh hasil jumlah vegetasi/ covercrop yang ada di kebun sawit berumur 7, 10 dan 14 tahun sebanyak 42 jenis yang bervariasi tiap umur tanaman sawit. Proporsi hijauan yang ada meliputi jenis rumput, legume dan paku-pakuan bervariasi pada tiap umur kebun sawit. Produksi hijauan yang ada di bawah kebun sawit berumur 7, 10 dan 14 tahun berturut-turut 2.571 kg/ha, 1.479,76 kg/ha dan 1.417,22 kg/ha dalam bentuk segar serta sebesar 811,41 kg/ha, 471,15 kg/ha dan 456,91 kg/ha dalam bahan kering. Kapasitas tampung dari kebun sawit berumur 7, 10 dan 14 tahun adalah 0,36 satuan ternak (ST)/ha, 0,21 ST/ha dan 0,20 ST/ha.Keywords: cover crops, oil palm plantation, forage, ruminant, dry season, Pelalawan

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