Hypomagnesaemia and Hypomagnesae-Mic Tetany Induced in Lactating Cows by Changing the Diet     

Inger W. Dishington  Sverre Tollersrud 《Acta veterinaria Scandinavica》1967,8(1):14

Thirty-five experiments are demonstrated in which high-lactating cows were exposed to abrupt changes from a normal dietary Mg supply to an extremely Mg-poor diet. The preliminary diet was adequate, supplying the cows with about 25 g Mg per day. The experimental feeding was individually calculated, containing 2.55 Mg for maintenance and 0.15 g for each kg of milk. Daily serum mineral analyses showed a pronounced hypomagnesaemia in all 35 experiments within 2 to 18 days. In 5 experiments there was a simultaneous fall in serum Ga, and the cows collapsed in tetany. The other 30 cases remained clinically healthy in spite of the low serum Mg level as long as the diet was given unchanged. In 25 cases these already hypomagnesaemic cows were exposed to a relatively high oral supplementation of Na₂HPO₄,Na₂SO₄ or both. In 9 cases the supply led to pronounced tetanic convulsions, in 4 cases a subtetanic state was observed, and in 4 cases the cows showed borderline symptoms, i.e., they reacted clinically as well as analytically immediately after the supply was given, but no attacks appeared, and the cows recovered as soon as normal fodder was given. In 8 cases the cows did not react to the “trigger” doses at all.The experiments are discussed and the reactions compared with those observed when high-lactating cows are let out on tetany-prone, (NH₄)₂SO₄-dressed pastures. The conclusion is drawn that a high Mg content in the diet prior to a Mg-deficient diet has little, if any, influence on the tendency to precipitate tetany. Considerable decreases in content, or availability, of dietary Mg always lead to decreases in serum Mg. Occasionally, under special unfavourable circumstances, when the drop in serum Mg is extraordinary rapid, the serum Ca level may drop as well and tetany occur without further stressing elements. In most cases, however, the results seem to support the suggestion that tetanic couvulsions are not conditioned entirely by the reduced availability of Mg but are to a great extent dependent upon the serum Ca-reducing effect of co-operating, so-called trigger compounds, simultaneously present in the diet. In this connection the addition of Na₂HPO₄ and Na₂SO₄ to the Mg-poor diet has been studied and found to confirm the suggestion made in earlier papers (Ender et al 1957; Dishington 1965) that the high content of Na, K, P, and S found in (NH₄)₂SO₄-dressed pasture grass seems to play a prominent part in making this grass tetany-prone.  相似文献   

Anesthesia induces stress in Atlantic salmon (<Emphasis Type="Italic">Salmo salar</Emphasis>), Atlantic cod (<Emphasis Type="Italic">Gadus morhua</Emphasis>) and Atlantic halibut (<Emphasis Type="Italic">Hippoglossus hippoglossus</Emphasis>)     

Inger Hilde Zahl  Anders Kiessling  Ole Bent Samuelsen  Rolf Erik Olsen 《Fish physiology and biochemistry》2010,36(3):719-730

Stress in response to anesthesia with benzocaine, MS-222, metomidate and isoeugenol was studied in Atlantic salmon (Salmo salar), Atlantic halibut (Hippoglossus hippoglossus), and Atlantic cod (Gadus morhua) with no concomitant stress from handling or confinement in association with anesthesia or sampling. All of the anesthetics tested induced a stress response in all species, displayed by a release of cortisol to the water. MS-222 anesthesia elicited the highest cortisol release rates, reaching maximum levels 0.5 h post-exposure and returning to basal levels after 3–4 h. Benzocaine anesthesia caused a bimodal response where the initial peak in cortisol release rate was followed by a second increase lasting towards the end of the trial (6 h). This bimodality was more profound in Atlantic salmon than in Atlantic halibut and Atlantic cod. Metomidate anesthesia induced the lowest release of cortisol of the agents tested in both Atlantic halibut and Atlantic cod, but resulted in a bimodal response in Atlantic salmon where the initial increase in cortisol release was followed by a larger increase peaking at 2–2.5 h post exposure before returning to basal levels after 5 h. The stress induced in Atlantic salmon by isoeugenol anesthesia resembled that of MS-222, but did not reach the same elevated level. Overall, the cortisol release was most profound in Atlantic salmon followed by Atlantic halibut and Atlantic cod.  相似文献   

Proteome analysis elucidating post-mortem changes in cod (Gadus morhua) muscle proteins   总被引：4，自引：0，他引：4  

Kjaersgård IV  Jessen F 《Journal of agricultural and food chemistry》2003,51(14):3985-3991

Proteome analysis was successfully applied to study the alterations in fish muscle proteins during ice storage. The processes occurring during post-mortem metabolism are known to lead to characteristic changes in the texture and taste of fish muscle. Endogenous proteases are anticipated to play the major role in these processes, although the exact mechanisms during fish meat tenderization have yet to be depicted. Protein changes in cod (Gadus morhua) muscle were followed during 8 days of storage. Within the partial proteome (pI 3.5-8.0, MW 13-35 kDa) significant changes were found in 11 protein spots. In nine protein spots the intensity increased, and for eight of these the increases were significant (p < 0.05) within the first 2 h post-mortem. In contrast, two protein spots decreasing in intensity showed significant (p < 0.03) changes after 8 days, thereby indicating that in the fish muscle different biochemical processes are involved in the protein changes observed post-mortem.  相似文献