Kirsi Partanen

Performance of growing–finishing pigs fed medium- or high-fibre diets supplemented with avilamycin, formic acid or formic acid–sorbate blend

Abstract A total of 160 growing–finishing pigs with initial body weights of 27 kg and originating from eight farms were used in a performance trial to investigate the effects of dietary fibre content (medium or high) and growth-promoting feed additives (none, avilamycin, formic acid or formic acid–sorbate blend) on pig growth, the feed to gain ratio and the incidence of diarrhoea. Medium-fibre grower and finisher diets [188 and 196 g neutral detergent fibre (NDF)/kg dry matter (DM)] were composed of barley and soybean meal and the respective high-fibre diets (239 and 284 g NDF/kg DM) of barley, oats, barley fibre, peas, soybean meal and vegetable oil. Both medium- and high-fibre diets were similar in net energy (8.7 MJ/kg) and ileal digestible lysine content (8.0 and 6.6 g/kg for grower and finisher diets, respectively). Avilamycin (40 mg/kg) was added to grower diets only whereas formic acid (8 g/kg) and formic acid–sorbate blend (8 g/kg formic acid and 0.4 g/kg potassium sorbate) were added to both grower and finisher diets. No diet×additive interactions were observed in the performance or carcass characteristics of pigs. Dietary fibre content did not affect the growth or feed to gain ratio of pigs. In the growing period, pigs fed diets with avilamycin, formic acid or formic acid–sorbate blend grew faster and had a lower feed to gain ratio than did those fed diets without additives. The differences between the additives were not significant. In the finishing period, pigs fed acidified diets grew faster and utilised feed more efficiently than did those in the avilamycin group. Furthermore, formic acid–sorbate blend enhanced pig performance more than did plain formic acid. For the total fattening period, the average growth rates were 856, 878, 896 and 930 g/day and the feed to gain ratios 2.55, 2.51, 2.43 and 2.32 kg DM/kg gain for diets without additives and with avilamycin, formic acid and formic acid–sorbate blend, respectively. Additives improved the growth and feed to gain ratio compared to diets without additives. Performance was better with organic acid supplementation of grower and finisher diets than with avilamycin supplementation of grower diet only. In addition, formic acid–sorbate blend improved the feed to gain ratio more than did plain formic acid. In the growing period, additives decreased the incidence of diarrhoea in the medium-fibre diet. In the high-fibre diet, the incidence of diarrhoea was generally low, except in the avilamycin treatment. We concluded that formic acid and formic acid–sorbate blend were equally effective alternatives to the antibiotic avilamycin in grower diets. Since organic acids can be added to finisher diets as well, their use resulted in further improvements in pig performance compared to avilamycin which can be used in grower diets only. The efficacy of formic acid as a growth promoter was intensified with sorbate addition.

Comparison of Aspergillus niger phytase and Trichoderma reesei phytase and acid phosphatase on phytate phosphorus availability in pigs fed on maize‐soybean meal or barley‐soybean meal diets

The efficacy of Aspergillus niger (APhy) phytase, Trichoderma reesei (TPhy) phytase and acid phosphatase (TAcPh) preparations in improving the utilization of phytin-phosphorus in the maize-soybean meal (SBM) or barley-SBM (800:200 g kg-1) diets was studied in two separate digestibility and balance trials with ten growing pigs using 5 x 5 Latin square designs. The positive control diet contained a total phosphorus (P) of 6.5 g kg-1, while the negative control as well as the APhy, TPhy and TAcPh supplemented diets which did not contain additional inorganic-P, had a total P of 4.1 g kg-1. The APhy and TPhy supplements provided phytase activity of 1000 PU g-1 together with AcPh of 8000 HFU g-1. TAcPh at a level of 8000 HFU g-1 was the only addition to one diet. The intrinsic phytase activity of barley was 355 PU g-1 while maize and soybean meal showed no phytase activity. Phytase supplements of the APhy and TPhy sources increased ash digestibility in both diets but had only a minor effect on nitrogen utilization. The addition of phytase improved absorption of P by 21%-units in barley-SBM diet and 29%-units in maize-SBM diet, without any difference between the two phytase sources. The retained P in diets with phytase was higher than in diets without phytase, 4.4 (APhy), 4.5 (TPhy) vs. 2.9 g d-1 in barley-SBM-diets and 3.7 (APhy), 4.0 (TPhy) vs. 1.8 g d-1 in maize-SBM-diets. No difference was found between the two sources of phytase. TAcPh without additional phytase did not show any effect on P absorption or retention. Ca absorption and retention were improved due to the phytase treatments. Supplementing pig diets with either APhy or TPhy sources seems to be equally effective in enhancing the availability of phytate-P. Consequently, these supplements can reduce the P-excretion of pigs by 32-40% as compared with the diet supplemented with inorganic-P.

Carcass and meat quality traits of four different pig crosses

The study compared properties of Finnish Landrace×Yorkshire crossbred sows mated with Finnish Landrace (FL), Norwegian Landrace (NL), Norwegian Duroc×Norwegian Landrace (NDL), or Swedish Hampshire (SH) boars. The focus was to study the cross-sectional area of loin, cross-sectional area and number of muscle fibres, loin colour and pH value as well as the ratio of water to protein in the loin. The four studied crosses were quite similar having only small differences in carcass and meat quality. The carcass lean content was the lowest in NDL. The loins of FL and NL were longer than the loins of NDL and of SH. The cross-sectional area of loin was the largest in SH. The loin of FL was lighter in colour and the loin of SH was redder than the loins of the other crosses studied. The protein content was lower and the ratio of water to protein higher in loin of SH than in the other crosses.

Feeding weaned piglets and growing-finishing pigs with diets based on mainly home-grown organic feedstuffs

In 2000, EU regulations for organic animal production set new guidelines for organic pig feeding requiring that this be based on mainly home-grown organic feedstuffs. Doubts were however raised whether these feeding regimes can maintain good growth performance and carcass quality of pigs. Three experiments were carried out to study different organic feeding regimes in weaned piglets and fattening pigs. In Experiment 1, we evaluated the use of peas and faba beans (0, 120, or 240 g kg-1) in diets for weaned piglets. Piglets fed pea diets performed as well as those fed the control diet, whereas the highest faba bean level resulted in reduced feed intake and growth performance. In Experiment 2, we studied the replacement (0, 33, or 67%) of rapeseed cake with blue lupins in fattening pig diets. The dietary lupin level had a quadratic effect on the weight gain of growing pigs, the best performance being observed at the 33% replacement level. However, dietary lupin level did not influence weight gain during the finishing period and total fattening. Back fat became softer with increasing dietary lupin levels. In Experiment 3, different protein supplements were compared in organic diets from weaning to slaughter. In two-phase feeding, the best performance was observed when whey protein was used as the protein supplement, followed by soya bean cake + whey protein and rapeseed cake + fish meal. The effects of a one-phase organic feeding regime with cold-pressed rapeseed cake + whey protein did not differ from those of the two-phase organic feeding regimes. Fattening pigs fed organic diets required from two to seven days longer to reach slaughter weight than those fed conventional diets. Pigs fed organic diets had fatter carcasses, but the eating quality of organic pork did not differ from that of pork from pigs fed conventional diets. Feed costs and the circulation rate of pigs, weaners in particular, were greater and carcass prices lower in the organic feeding regimes than in the conventional ones.

Effects of finishing diet and pre-slaughter fasting time on meat quality in crossbred pigs

The effects of the carbohydrate composition of finishing diet (fed from 80 to 107 kg of body weight) and the length of pre-slaughter fasting on pork quality were studied in a 2 × 2 factorial experiment with 80 crossbred pigs. The control finishing diet was based on barley and soybean meal, and the fibrous finishing diet was based on barley, barley fibre, faba beans, and rapeseed cake. These diets contained 465 and 362 g starch and 177 and 250 g dietary fibre per kg, respectively. The fasting times of 25 and 41 h were obtained by giving the pigs their last meal at different times. Longer fasting lowered the glycolytic potential of the longissimus lumborum muscle (P = 0.01), whereas the finishing diet had no effect. Different muscles responded differently to the treatments. Longer fasting increased the ultimate pH of the semimembranosus muscle (P = 0.02), but did not affect that of the longissimus lumborum and semispinalis capitis muscles. The finishing diets did not affect the ultimate pH of the investigated muscles. A diet × fasting time interaction was seen in the lightness of the semimembranosus muscle (P = 0.05). The fibrous diet resulted in darker meat than the control diet did in pigs that were fasted for 25 h (P < 0.05). Longer fasting darkened the meat colour in pigs fed the fibrous diet (P < 0.05) but not in those fed the control diet. The meat from the semispinalis capitis muscle was darker in pigs fed the fibrous than those fed the control diet (P = 0.04). The treatments did not affect the colour of the longissimus lumborum muscle. Longer fasting decreased drip loss from the meat of pigs fed the control diet (P < 0.05). The eating quality of the pork was not influenced by the finishing diets or the fasting time. The pigs also grew equally fast on both finishing diets. In conclusion, a moderate alteration in the carbohydrate composition of a finishing diet or longer pre-slaughter fasting can have some effects on pork quality in crossbred pigs, but these effects vary in different muscles.

Effects of phosphorus level and microbial phytase supplementation on the performance and bone mineralization in pigs

An experiment was conducted with 192 growing and finishing pigs in order to evaluate the phosphorus (P) requirement of the pigs and the efficacy of Aspergillus niger phytase on a barley based diet, and to study phase feeding of P and phytase. The performance of the pigs and certain chemical and physical parameters of their tibia and fibula bones were used as criteria for the effectiveness of the treatments. The variables in diet formulation were microbial phytase addition of 500 FTU kg−1 (‐/+ ) and three P levels—high (HP), medium (MP) and low (7.7, 6.1 and 4.5 g of total P kg−1 dry matter, respectively). Two additional diets were combinations of the former: MP—LP—and MP + LP —. The medium P level was sufficient for the pigs from 30 kg up to slaughter at 100 kg with the growth level of 900 g day and feed conversion ratio (FCR) of 2.60, but the lowest P level led to an impaired average daily gain (ADG) and FCR. Microbial phytase improved the ADG (P < 0.05) and FCR of pigs (P < 0.05) on LP diet. No signs of...

The Effect of Ash Content on the Nutritive Value of Meat and Bone Meal for Growing Pigs

Abstract A balance experiment was conducted with 9 barrows at live weight from 25 to 75 kg. The experiment had a 9 × 6 cyclic change-over design and the treatments were arranged factorially. The factors were three protein sources: soya bean meal (SBM), low ash meat and bone meal [MBL, 208 g ash/kg dry matter (DM)], and high ash meat and bone meal (MBH, 330 g ash/kg DM); and three protein supplementation levels: 20, 45 and 70 g crude protein/kg DM. The apparent digestibility of crude protein was SBM 0.897, MBL 0.755 and MBH 0.748. The nitrogen (N) retention increased linearly (p<0.001) as N intake increased, but the rate of increase was steeper for SBM diets compared with MBL and MBH diets. The pigs given MBH diets retained more N than those given MBL diets (p < 0.05), but no differences were observed in the rate of increase. The apparent digestibility of crude fat was SBM 0.729, MBL 0.690 and MBH 0.279. The determined digestible energy contents were SBM 16.62, MBL 13.38 and MBH 9.47 MJ/kg DM. The calcium,...

Heart size and mean muscle fibre cross-sectional area related to birth weight in pigs

One of the aims in domestic pig breeding has been to increase the size of litters resulting in variation in birth weight of piglets. Pig breeding has also resulted in increased body muscle mass. Muscles with the same size can consist either of large number of thin muscle fibres or small number of thick muscle fibres. Larger body muscle content means that in living animal the heart must pump blood to larger muscle mass than earlier. Our interest in this study was to investigate the relationship between the pig’s birth weight and (i) growth performance and carcass composition, (ii) the size of organs, and (iii) the mean muscle fibre cross-sectional area at slaughter. The study consisted of twenty pigs slaughtered at the age of 165±2 days. The day after the slaughter, the carcass composition was determined by dissecting the chilled carcass into lean, fat, bones, and skin and organs were weighed. The average cross sectional area of muscle fibres was determined from three fast-twitch muscles longissimus dorsi, semimembranosus, gluteus superficialis, and two slow-twitch muscles infraspinatus and masseter. The birth weight of pigs ranged from 0.9 to 2.2 kg. We found no clear relationships between the birth weight and the pig’s growth performance from birth to slaughter. When the birth weight increased the heart weight at slaughter increased as well (P < 0.01). The heart weight was higher in those pigs with high carcass weight (P < 0.05) and with the high weight of total muscle mass in the carcass (P < 0.001). The cross sectional area of muscle fibres in M. longissimus dorsi (P < 0.05), M. semimembranosus (P < 0.10), and M. gluteus superficialis (P < 0.05) was larger in those pigs with low birth weight compared to those found in pigs with high birth weight.

Effects of some organic acids and salts on microbial fermentation in the digestive tract of piglets estimated using an in vitro gas production technique

An in vitro gas production technique was used to screen different organic acids (formic, propionic, lactic, citric, and fumaric acid), organic salts (calcium formate, potassium sorbate, and sodium benzoate), and inorganic phosphoric acid for their ability to modulate microbial fermentation in the digestive tract of piglets. For the incubation, 40 ml of culture medium (53% buffer, 45% frozen ileal digesta, and 2% fresh faeces) was dispensed in vessels containing 5 ml of buffer, 0.5 g of feed, and 20 µl of liquid or 20 mg of solid acidifiers. Gas production was measured every 15 min during the 24 h incubation at 39°C, and a Gompertz bacterial growth model was applied to the gas production data. Formic acid was the only acid that reduced the maximum rate of gas production (µm) compared to that in the control treatment (P 0.05). When investigating formic-acid-based mixtures that contained 1–5% of potassium sorbate and/or sodium benzoate, the estimated parameters for the Gompertz growth model did not differ from those for treatments with plain formic acid (P > 0.05). However, concentrations of total volatile fatty acids, acetic acid, propionic acid, and n-butyric acid were reduced by all the mixtures (P 0.05). In conclusion, organic acids and salts were found to differ in their ability to modulate microbial fermentation in the digestive tract of piglets. Mixing formic acid with potassium sorbate or sodium benzoate changed fermentation patterns, and the possibility to use them to enhance the antimicrobial effect of formic acid should be investigated further in vivo.